# do you have intel c state disabled or enabled?



## xzamples

i don't know how i feel about intel c-state, im just trying to get a consensus of how many people actually have this feature enabled


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## Hattifnatten

yep


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## Luciferxy

I disabled it, C1E & C state, but EIST on.


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## QxY

C7s enabled here, along with the Windows power saving feature that downclocks the CPU...I get some really cool 4770k idle temps at 800MHz/0.15v. Not sure why someone would want to run at full speed/voltage all the time.


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## GeneO

EIST, C1E, C3 enabled, C6 and C7 disabled as they are much higher latency.


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## PachAz

I have all "tree-hugging" features disabled, because I feel that you get the best stability in OC then.


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## TheCautiousOne

I have been messing around with the cstates that you speak of. I have finally been able to get my computer to "sip" juice as the overclocking guide I was following stated.
Quote:


> Originally Posted by *QxY*
> 
> C7s enabled here, along with the Windows power saving feature that downclocks the CPU...I get some really cool 4770k idle temps at 800MHz/0.15v. Not sure why someone would want to run at full speed/voltage all the time.


He said it best right here. I am using .144v to .444v running windows task manager, cpu-z, firefox, i tunes never breaking the .5v mark







My core mulitplier is set to 44 with a max of 1.213v: I had to go into the BIOS (1504) for the FORMULA VI and enable c state 7 (C7s)

I am actually pretty excited. I've been wanting to do this for a while.


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## jhaze84

I have all power-saving features enabled in BIOS that I possibly can, including all the C-states. I pay the electric bill and I'd rather not be giving away money for no reason. I also put my computer to sleep when I'm not at home. I don't like the idea of wasting power and reducing component lifespan by running my system at full blast all the time, especially when I'm not using it.

I know a lot of computer enthusiasts, especially overclockers, don't mind turning off the power-savings to chase every last drop of performance. But I think it's more elegant and impressive to have a stable overclock while also being power efficient. My opinion of course.


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## Prophet4NO1

Power is cheap. At idle my rig runs at a constant 4.6 Ghz. With 3 780's it pulls about 200 watts at idle. Only dropped to 150 watts with c states on. Rathe have it slightly more snappy than use I tiny bit less power. But that's me.


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## ski-bum

Quote:


> Originally Posted by *jhaze84*
> 
> I have all power-saving features enabled in BIOS that I possibly can, including all the C-states. I pay the electric bill and I'd rather not be giving away money for no reason. I also put my computer to sleep when I'm not at home. I don't like the idea of wasting power and reducing component lifespan by running my system at full blast all the time, especially when I'm not using it.
> 
> I know a lot of computer enthusiasts, especially overclockers, don't mind turning off the power-savings to chase every last drop of performance. But I think it's more elegant and impressive to have a stable overclock while also being power efficient. My opinion of course.


This^

It's also simple more wear & tear on your parts.


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## fateswarm

It does nothing to the stability of what I'm doing so I use it. Also it helps enormously on longevity. It may not seem immediately, but it does across years.

I have killed a computer by turning off all power saving features for a year or two.

Plus lower temps/noise is not just about "power is cheap".


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## spin5000

I have all C states disabled I dont even understand the point of them. I can set my MHz in windows power options, I can set wether I want the CPU frequency and voltage to dynamically change or not based on load, I can set if I want cores to be automatically parked or not based on load and how many cores as well.

I can do all that without C-States so I don't even understand what I'm missing out on by disabling them.


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## Luciferxy

^^ seconded.

Eist & windows power option works well to reduce clock speed.


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## jhaze84

C states are processor idle states. The more C states you have enabled, the more aggressively your CPU can throttle down its power usage when it is idle. When it detects computer activity (a hardware interrupt), it will throttle back up to C0 (full power state). If you disable C states, your CPU will be in C0 state all the time. A Google search for C states will have more technical explanations.


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## Prophet4NO1

Quote:


> Originally Posted by *fateswarm*
> 
> It does nothing to the stability of what I'm doing so I use it. Also it helps enormously on longevity. It may not seem immediately, but it does across years.
> 
> I have killed a computer by turning off all power saving features for a year or two.
> 
> Plus lower temps/noise is not just about "power is cheap".


temps barely go up since its no under load. Still idles at around 30-35C. So noise is not an issue. These chips are so efficient these days they don't put out much heat when not actually doing anything. All my fans run just above stall speed unless I am gaming or doing some other heavy activity. Even then I only run the fans on my H220 at about 50-60% most of the time. And since I buy overkill motherboards, like my Rampage, I'm not overly worried about killing it. Cheap motherboards are a bit more of a problem. Buy good stuff, crank things to 11 and enjoy.


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## fateswarm

Temps don't kill, voltage does, according to Intel engineers. This is theoretically not true, since temp can kill, but they mean the way those chips usually operate, most of the time voltage is the one that kills in overclocking, not temps. This is because they auto-throttle anyway after a point, and that point is not extremely dangerous, plus we have obvious proof from LN2 overclocking that even subzero will kill on high voltage.


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## Prophet4NO1

Quote:


> Originally Posted by *fateswarm*
> 
> Temps don't kill, voltage does, according to Intel engineers. This is theoretically not true, since temp can kill, but they mean the way those chips usually operate, most of the time voltage is the one that kills in overclocking, not temps. This is because they auto-throttle anyway after a point, and that point is not extremely dangerous, plus we have obvious proof from LN2 overclocking that even subzero will kill on high voltage.


True, and more voltage makes more heat and that stresses things like the VRM on the board. But high quality boards have VRMs capable of safely delivering way more power the the chips ever will, even for sub zero. At least most do. So, low odds having issues there. And on the CPU side, you need to be cranking voltage pretty hard to have an issue. Stay in the "safe zone". Or, maybe if the machine is on 24/7. But, my rig is off when I'm not around. In close to 20 years with PC, I have never killed a CPU outside running massive voltage.


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## fateswarm

I won't bother analyzing the several logical fallacies there.


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## TheCautiousOne

Quote:


> Originally Posted by *fateswarm*
> 
> I won't bother analyzing the several logical fallacies there.

















I understand. Fateswarm.. Cstates yay or nay? Lol


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## opt33

All power savings disabled. When Im using my computer it will be at full overclock speed. When Im not using my computer, it goes into auto sleep and powers down. Power states would only save few dollars per year, it is collectively green, but not helpful to an individual. Using sleep mode is a significant power savings to individual.

Also if overclocking using adaptive voltage with C states, you cant just test your overclock with a static load program like prime. Because you now have 2 things to test instead of 1. You have to test your overclock at full load (ie prime) to ensure enough volts at full load, but now also 2) you then have to test that for each increment in load, the scaled supplied voltage is appropriate for that given Mhz. Another more recent reason people run prime stable, then crash during intermittent load, because they failed to test at various different loads using their adaptive settings (which will give various vcores to various mhz settings, none of which were tested while at full load using prime).

However, power savings feature are great for portables where small power savings are helpful to battery life. But then running at stock, hence doesnt matter for anything other than improves battery life.


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## jasjeet

Quote:


> Originally Posted by *opt33*
> 
> All power savings disabled. When Im using my computer it will be at full overclock speed. When Im not using my computer, it goes into auto sleep and powers down. Power states would only save few dollars per year, it is collectively green, but not helpful to an individual. Using sleep mode is a significant power savings to individual.
> 
> *Also if overclocking using adaptive voltage with C states, you cant just test your overclock with a static load program like prime. Because you now have 2 things to test instead of 1. You have to test your overclock at full load (ie prime) to ensure enough volts at full load, but now also 2) you then have to test that for each increment in load, the scaled supplied voltage is appropriate for that given Mhz. Another more recent reason people run prime stable, then crash during intermittent load, because they failed to test at various different loads using their adaptive settings (which will give various vcores to various mhz settings, none of which were tested while at full load using prime).*
> 
> However, power savings feature are great for portables where small power savings are helpful to battery life. But then running at stock, hence doesnt matter for anything other than improves battery life.


This is absolutely correct and the reason why most tend not to use the C States. However i tend to use my PC with intermittant loads the most, so i have as much power saving features enabled as possible even on a 4.8Ghz OC. Then i use Prime95 and various other tests, such as gaming benchmarks, realbench, encoding, that dont utilise every drop of performance allowing me to test the transient loads on the chip. A lot of chips tend to lose the ability to use C States at higher OCs for the reasons opt33 has written.


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## GeneO

Quote:


> Originally Posted by *fateswarm*
> 
> I have killed a computer by turning off all power saving features for a year or two.


How do you know that is what killed your computer?


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## Sp33d Junki3

All C state is turned off. I use EIST and Windows power saver.
My system is all 24/7, never sleeps. No reason to run at max all the time, when I'm not using it or when I'm asleep.


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## Xtreme21

Everything but C1E and EIST.


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## tp4tissue

Save a few bux a year VS more stability, lower latency

***That 's what it comes down to.. because the OTHER aspects are not tangible..

Durability:

Not valid, because it will become obsolete before it dies..

Heat:

Not valid, CPU spends 90% of the time idling,
___________wattage is about equal on Cpu Idle with or without c states

Go Green:

Stay home, play computers, stop paying for arab oil to drive everywhere.. THAT is the greenest thing you can do..









C-states won't put a dent in the oil..


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## Prophet4NO1

Gas is just a byproduct of oil production. Most the oil we produce, btw US just became the #1 oil producer in the world, is sent over seas to be made into plastics and other things. Gasoline is just one of the leftovers you get. Well, a crude form of gasoline. More refining is done before it becomes what you put in your vehicle. Even if you changed every car on the road to electric, the demand for oil would be pretty close to the same.


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## opt33

another reason I dont use adaptive + power savings....kills ssd performance on every system I tested it on, hitting the most important speeds, small random read/write.
4k random read decreased 25%, 4k random write decreased 50% with power savings enabled vs not. different mobos will handle differently, but all ones I have owned, the result isnt pretty. As tp4tissue pointed out, power states increase latency.

Sandisk extreme pro SSD 480gb

no power savings, 4.7ghz


power savings enabled, 4.7ghz adaptive


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## jasjeet

That's very interesting on the SSD performance, I will test it on my system.


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## Sp33d Junki3

Well I did test your theory on the difference. I did not think that this would be that different.
I did 3 tests each, finding the top result.
EIST, CPU C1E, CPU C3 Report, CPU C6 Report, Package C State Support and Windows Processor Power Management (5% and 100%)

All Enabled, Windows Power at 5%


All Disabled, Windows Power at 100%


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## opt33

Quote:


> Originally Posted by *Sp33d Junki3*
> 
> Well I did test your theory on the difference. I did not think that this would be that different.
> I did 3 tests each, finding the top result.
> EIST, CPU C1E, CPU C3 Report, CPU C6 Report, Package C State Support and Windows Processor Power Management (5% and 100%)


yep, your getting similar results, but each mobo/bios handles it a little differently so percentage is different. It is access times/latency that causes the issue. You have a 14% decrease in 4k random read, and 36% decrease in 4k random write, still a huge decrease given random small read/write makes up a larger percentage of use.


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## fateswarm

Quote:


> Originally Posted by *GeneO*
> 
> How do you know that is what killed your computer?


You know because the exact same load under the exact same conditions killed it at a later date.

The whole universe deteriorates after a point, every structure will meet its entropy fall.

Higher temperature and voltage accelerates its "metabolism".


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## GeneO

Quote:


> Originally Posted by *fateswarm*
> 
> You know because the exact same load under the exact same conditions killed it at a later date.
> 
> The whole universe deteriorates after a point, every structure will meet its entropy fall.
> 
> Higher temperature and voltage accelerates its "metabolism".


What? What does this have to do with entropy and metabolism? I still don't understand how you know it isn't some other accumulative effect or due to some other reason like heat or... I would really like to know how you determined that. What were the symptoms?


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## fateswarm

Quote:


> Originally Posted by *GeneO*
> 
> What does this have to do with entropy and metabolism?


All structures collapse eventually. No voltage or frequency or temperature is 100% safe on a CPU. It's just that some are so close to 100% it's usually unnoticeable and enough for Intel to give out 3 year long warranties.


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## GeneO

Quote:


> Originally Posted by *fateswarm*
> 
> All structures collapse eventually. No voltage or frequency or temperature is 100% safe on a CPU. It's just that some are so close to 100% it's usually unnoticeable and enough for Intel to give out 3 year long warranties.


CPU degradation has nothing to do with "all things collapse eventually" - it is due to physical forces that occur operating the chip.

You still haven't answered my question on how you know your CPU died from turning off power saving states - I am interested in how you know it was that.


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## fateswarm

Quote:


> Originally Posted by *GeneO*
> 
> CPU degradation has nothing to do with "all things collapse eventually" - it is due to physical forces that occur operating the chip.
> 
> You still haven't answered my question on how you know your CPU died from turning off power saving states - I am interested in how you know it was that.


How can we proceed when we don't agree on the basics? It seems you want your own answers while being sarcastic.


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## GeneO

Quote:


> Originally Posted by *fateswarm*
> 
> How can we proceed when we don't agree on the basics? It seems you want your own answers while being sarcastic.


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## Wirerat

Quote:


> Originally Posted by *Sp33d Junki3*
> 
> Well I did test your theory on the difference. I did not think that this would be that different.
> I did 3 tests each, finding the top result.
> EIST, CPU C1E, CPU C3 Report, CPU C6 Report, Package C State Support and Windows Processor Power Management (5% and 100%)
> 
> All Enabled, Windows Power at 5%
> 
> 
> All Disabled, Windows Power at 100%


The ssd benchmark gives me varying results when I dont even change anything.


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## GeneO

Here is what I get for the various states, and what I compromise to.

All power saving states disabled:



All power saving started on. You can see the latency is pretty high:



C3 and EIST with a minimum processor state of 50% (1.8 GHz minimum processor speed):



And a bit of improvement over that with Intel Dynamic Storage Acceleration enabled in BIOS: EIST + C1E + C3 + 50% minimum + DSA:


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## opt33

yep, that is what I would do if using power savings....figure out a compromise that has least effect on latency.

Athough my power savings is when the computer goes into sleep mode, which saves me over $100 per year. Even if I use all power states enabled, only saves me $4.50 per year, assuming 6 hours of computer use per day. The other 18 hours my computer sleeps would be same.


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## fateswarm

For most people bills would be the 3rd concern. I'd put longevity and quieter fans the first two.


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## Sp33d Junki3

The difference from steady 1.22v to a fluctuation of 0.96-1.22v is really not going be a big factor.
Your ambient, overall circulation would be more an affect to the fan speed.
I can run my fans at 30%, be dead silent and still have temps low temps below 30c idle. But that will change based on my ambient temps.
Hotter it gets, higher my temps. So fans have to run faster.

By doing this, I saw no difference in temps by having all energy savings off or on.


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## Prophet4NO1

Quote:


> Originally Posted by *fateswarm*
> 
> For most people bills would be the 3rd concern. I'd put longevity and quieter fans the first two.


As I have said, none of my hardware has ever died from power saving being off. I burned out mobos that where not good enough to handle the over clocking was trying. Things like that. But daily rigs with all that stuff off have never crapped out. And if by some chance it ever happens, I can afford new parts.


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## Peen

Just FYI, on Haswell with C-states enabled and "High Performance" enabled in Windows, you can maintain whatever you OC speed is but get up to 25w idle reduction.

I have confirmed this with watt meter, and using AS SSD my scores are exactly the same. Remember, I still have "High Performance" selected but with C states enabled in BIOS.


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## opt33

Quote:


> Originally Posted by *Peen*
> 
> Just FYI, on Haswell with C-states enabled and "High Performance" enabled in Windows, you can maintain whatever you OC speed is but get up to 25w idle reduction.
> 
> I have confirmed this with watt meter, and using AS SSD my scores are exactly the same. Remember, I still have "High Performance" selected but with C states enabled in BIOS.


which C states do you have enabled, or all?


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## Peen

All of them. And just to clarify my findings...

Fresh Windows 8.1 install with all updates.
4.8ghz Windows "High Perf" no C-states: Idle 155w, 30mb 4k in AS-SSD
4.8ghz Windows "High Perf" All C-states: idle 130w, 30mb 4k in AS-SSD
4.8ghz Windows "Balanaced" All C-states: Idle 129w 21mb 4k in AS-SSD

Moral of the story, keep windows on high performance with c-states on if you can especially on Haswell. I did latency tests before and they were identical but you get 25w drop in idle power usage.

This only applies to Haswell since it has voltage regulation on the CPU package itself!


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## Sp33d Junki3

Well that would not matter. Right now my cpu is using only 25w on idle, about 3% cpu load.
All C State and EIST off. I do prime and my cpu jumps to 78w, 100% all cores.
I can see this in my UPS and watt meter the difference.


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## djriful

For me is ON or AUTO, I need it since my rig is a Plex.tv server running 24/7 so I need it to idle low power as it can and no temperature change in the room. I am still clocking at 4.6-4.8Ghz with these C-State on. I don't have much stability problem. Very solid board and cpu.


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## Peen

Quote:


> Originally Posted by *Sp33d Junki3*
> 
> Well that would not matter. Right now my cpu is using only 25w on idle, about 3% cpu load.
> All C State and EIST off. I do prime and my cpu jumps to 78w, 100% all cores.
> I can see this in my UPS and watt meter the difference.


You have Ivy Bridge, so no difference. But Haswell is a large drop in idle wattage for free. No performance penalty in anything I've benchmarked. But even for Haswell you have to have High Performance selected in Windows power management.


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## opt33

Quote:


> Originally Posted by *Peen*
> 
> All of them. And just to clarify my findings...
> 
> Fresh Windows 8.1 install with all updates.
> 4.8ghz Windows "High Perf" no C-states: Idle 155w, 30mb 4k in AS-SSD
> 4.8ghz Windows "High Perf" All C-states: idle 130w, 30mb 4k in AS-SSD
> 4.8ghz Windows "Balanaced" All C-states: Idle 129w 21mb 4k in AS-SSD
> 
> Moral of the story, keep windows on high performance with c-states on if you can especially on Haswell. I did latency tests before and they were identical but you get 25w drop in idle power usage.


yep, nice find, that solves the issue on mine as well.

All C states enabled, EIST off, idle HWM power cpu package only 3-4W. SSD 1129.
All C states disabled, EIST off, idle HWM power cpu package only 30W. SSD 1131, ie basically same performance.

It looks like that is the way to go if using power savings.


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## fateswarm

Quote:


> Originally Posted by *Prophet4NO1*
> 
> As I have said, none of my hardware has ever


Your sample of 1 or 4 is insignificant. Statistics are important after 20 or 40 samples. And it depends on the level of stress, e.g. I had a GPU stressed above spec for a few months and I killed it.


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## tp4tissue

Quote:


> Originally Posted by *Peen*
> 
> All of them. And just to clarify my findings...
> 
> Fresh Windows 8.1 install with all updates.
> 4.8ghz Windows "High Perf" no C-states: Idle 155w, 30mb 4k in AS-SSD
> 4.8ghz Windows "High Perf" All C-states: idle 130w, 30mb 4k in AS-SSD
> 4.8ghz Windows "Balanaced" All C-states: Idle 129w 21mb 4k in AS-SSD
> 
> Moral of the story, keep windows on high performance with c-states on if you can especially on Haswell. I did latency tests before and they were identical but you get 25w drop in idle power usage.
> 
> This only applies to Haswell since it has voltage regulation on the CPU package itself!


hey .. could you test balanced no c states? does that affect it?


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## Prophet4NO1

I have built way more than a few machines. Lol. Rough number, including rebuilds, around 30-40. Some I have sold off. Others cannibalized. Couple still have in a closet. And I have build a ****load more for others. Its amazing how much you can do in 20 years.


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## opt33

Quote:


> Originally Posted by *tp4tissue*
> 
> hey .. could you test balanced no c states? does that affect it?


If C states/eist are not active, balanced doesnt matter. I get same score with high performance and balanced performance with power savings off. Only with power savings on do you need to change to high performance to prevent high latency/lower ssd speed.


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## GeneO

Quote:


> Originally Posted by *fateswarm*
> 
> Your sample of 1 or 4 is insignificant. Statistics are important after 20 or 40 samples. And it depends on the level of stress, e.g. I had a GPU stressed above spec for a few months and I killed it.


Don't mean to start an argument here, but I think it is a bit more significant than your 1/1 processor dying that had power savings disabled but that you can't tell for sure why it died.


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## fateswarm

Quote:


> Originally Posted by *GeneO*
> 
> Don't mean to start an argument here


You do mean it. Anyway, voltage can kill on its own without temps.

http://en.wikipedia.org/wiki/Electromigration


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## deepor

I have C3/C6 enabled, C1E/EIST disabled. This is on Ivy Bridge with fixed voltage.

From what I could see, the vast majority of power saving is done by C3/C6/C7. The C1E and EIST features that can reduce clocks will not do as much power saving, but you can still see a difference in idle temperatures with offset voltage, so that's nice. C1E/EIST will increase latency numbers you see in LatencyMon by a lot. C3/C6 will not increase latency as much or not at all, so seems to work pretty well.

I grouped C1E and EIST together, but EIST is the feature that is needed for the Windows power profile settings to do something to the CPU clocks. C1E is automatic and done by the CPU itself. It seems when a CPU gets woken up, because of C1E it will run at reduced clocks for a tiny bit until voltage ramps up and it can switch to full speed. That tiny moment is enough for latency to look a bit bad in LatencyMon. That shouldn't really happen while gaming as there should be at least one core running at full load most of the time, and there's only one clock for all cores, so if a core gets woken up to deal with a device, it will start at full speed.

I'm using fixed voltage at the moment, as the best I could manage through offset voltage would still occasionally have a higher max. voltage getting recorded in monitoring software. Because of this, I thought it might be better for longevity to use fixed voltage for my CPU to not be so close to 1.4V vcore. If I would use offset voltage, I'd keep C1E/EIST enabled to reduce voltage at idle.


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## opt33

Looks like the setting on balanced performance that results in SSD performance decrease is "minimum processor state" of 5% vs in "high performance" it is set to 100%.

Using "high performance" as Peen stated or using "balanced performance" and changing min processor to 100% from 5%, both gives idle wattage of 5W without affecting SSD speed.


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## GeneO

Quote:


> Originally Posted by *fateswarm*
> 
> You do mean it. Anyway, voltage can kill on its own without temps.
> 
> http://en.wikipedia.org/wiki/Electromigration


You are diverting the subject again,

You should read that article you linked to. Electromigration depends on current. No current, no electromigration and the MTTF becomes infinite. You can have whatever voltage on your chip but with little load therefor little current, it won't cause any significant electormigration. Also , at absolute 0 temperature, that is "without temps", the MTTF is infinite. This is because the metallic ions are frozen in the lattice at absolute zero, and cannot be dislodged by the electron current . So voltage can't kill via electromigration "without temps".


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## Bit_reaper

I used to run with C-state, speed step and all that jazz disabled as it allowed me to reach higher clock speeds. Now I have an more modest OC going with most of the power saving features enable as its an hot summer and I don't want to roast my self alive


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## opt33

Quote:


> Originally Posted by *deepor*
> 
> I have C3/C6 enabled, C1E/EIST disabled. This is on Ivy Bridge with fixed voltage.
> 
> From what I could see, the vast majority of power saving is done by C3/C6/C7. The C1E and EIST features that can reduce clocks will not do as much power saving, but you can still see a difference in idle temperatures with offset voltage, so that's nice. C1E/EIST will increase latency numbers you see in LatencyMon by a lot. C3/C6 will not increase latency as much or not at all, so seems to work pretty well.
> 
> I grouped C1E and EIST together, but EIST is the feature that is needed for the Windows power profile settings to do something to the CPU clocks. C1E is automatic and done by the CPU itself. It seems when a CPU gets woken up, because of C1E it will run at reduced clocks for a tiny bit until voltage ramps up and it can switch to full speed. That tiny moment is enough for latency to look a bit bad in LatencyMon. That shouldn't really happen while gaming as there should be at least one core running at full load most of the time, and there's only one clock for all cores, so if a core gets woken up to deal with a device, it will start at full speed.
> 
> I'm using fixed voltage at the moment, as the best I could manage through offset voltage would still occasionally have a higher max. voltage getting recorded in monitoring software. Because of this, I thought it might be better for longevity to use fixed voltage for my CPU to not be so close to 1.4V vcore. If I would use offset voltage, I'd keep C1E/EIST enabled to reduce voltage at idle.


Just tried that. I just enabled C6/C7 only. C1E, EIST, C3 disabled. returned to default "balanced profile". I have a manual OC at 4.7ghz, 1.29v, fixed vcore, fixed OC, no turbo, no adaptive voltage.

idle wattage 4-5W, my vcore via multimeter is reading .5 to .4v and HWM reads my vcore as .2 to .6. SSD performance is normal, no decrease at all in any tests. (cpuz still reads vid max 1.29, but that shouldnt change).

With C6/C7 disabled, idle wattage 33-35W, multimeter reads vcore 1.292v, HWM reads vcore 1.296.

Looks like easiest to do is just enable C6/C7 only, that does 98% of power savings, no hit in latency, and does decrease vcore even on my manual OC. My mhz still says 4700, but have been told by programmers that 4700 isnt really there until loaded, but not interested in that esoteric.


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## fateswarm

Quote:


> Originally Posted by *GeneO*
> 
> at absolute 0 temperature, that is "without temps", the MTTF is infinite.


There is no absolute 0 in overclocking. There is always current and temps.


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## GeneO

Quote:


> Originally Posted by *fateswarm*
> 
> There is no absolute 0 in overclocking. There is always current and temps.


You missed my point entirely.


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## fateswarm

Quote:


> Originally Posted by *GeneO*
> 
> You missed my point entirely.


Let's put it down to facts. LN2 overclocking can kill within 24 hours a chip by using very low load, and hence low current, on very low temperatures and very high voltage. What is the mechanism?

My hunch is it's the energy potential of very high voltage, even if the current is only modest.


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## GeneO

Quote:


> Originally Posted by *fateswarm*
> 
> Let's put it down to facts. LN2 overclocking can kill within 24 hours a chip by using very low load, and hence low current, on very low temperatures and very high voltage. What is the mechanism?
> 
> My hunch is it's the energy potential of very high voltage, even if the current is only modest.


The mechanism is not electormigration, it is likely diaelectric breakdown or thermal stressing combined with this .
Do you have some reference to such LN2 at low load and very high voltage has killed a chip you are talking about. ?


----------



## fateswarm

Quote:


> Originally Posted by *GeneO*
> 
> it is likely diaelectric breakdown


That sounds good.


----------



## fateswarm

This sounds related. http://en.wikipedia.org/wiki/Time-dependent_gate_oxide_breakdown

I found it when I was searching dielectric breakdown in reference to this.


----------



## GeneO

Quote:


> Originally Posted by *fateswarm*
> 
> That sounds good.


Quote:


> Originally Posted by *fateswarm*
> 
> This sounds related. http://en.wikipedia.org/wiki/Time-dependent_gate_oxide_breakdown
> 
> I found it when I was searching dielectric breakdown in reference to this.


That is different. What you linked to is from long term low field (low voltage) "long-time application of relatively low electric field"


----------



## tp4tissue

Quote:


> Originally Posted by *opt33*
> 
> If C states/eist are not active, balanced doesnt matter. I get same score with high performance and balanced performance with power savings off. Only with power savings on do you need to change to high performance to prevent high latency/lower ssd speed.


awesome thx for the info:thumb:


----------



## spin5000

Quote:


> Originally Posted by *jhaze84*
> 
> C states are processor idle states. The more C states you have enabled, the more aggressively your CPU can throttle down its power usage when it is idle. When it detects computer activity (a hardware interrupt), it will throttle back up to C0 (full power state). If you disable C states, your CPU will be in C0 state all the time. A Google search for C states will have more technical explanations.


I can do all that with C-States fully disabled (Post #12)

Maybe I'm not getting something...


----------



## jasjeet

Ive done the test on my rig and can confirm the latency caused with C States enabled and the performance drop on SSDs. I havent got an internet connection on that PC yet, but will upload the pics soon.
For me, the drop in SSD performance is not really too much of an issue because they are so fast anyways. Im using an old Intel SSD atm with a 15MB/s random 4k read, and it feels just as fast as my Crucial M4.


----------



## Agiel

ia have 3 of them off, only EIST is on ... can i ask the community ?

i got a GA B75M-HD3 along with i5 3570k when i rise de CPU Ratio from 3.4 to 3.6 (is the max my boad support) i boot to windows and the cpu ratio(with turbo on) never surpase the 3.60Ghz instead of 3.8 with turbo, why is that ?? i got 2x4GB Corsair Vengeance at 1600Mghz ...


----------



## deafboy

I used to leave all that stuff disabled, just wanted the clocks to remain constant. But I've since let them be. I haven't had the need for things to run at 4.8+ 24/7 for a while, lol.


----------



## r0cawearz

for me, leaving the c states off gives me more stable voltages. i can't run x264 for more than a couple of minutes with cstates on, but with them off, i can go for much longer


----------



## fateswarm

It does theoretically. It's a standard advice to turn them off for testing overclocking. In my current setup, it doesn't affect it, the only slightly relevant settings that greatly affect it are overcurrent and overvoltage protections and droop settings.


----------



## deepor

Quote:


> Originally Posted by *spin5000*
> 
> I can do all that with C-States fully disabled (Post #12)
> 
> Maybe I'm not getting something...


*About the tech:* (or at least how I understood it)


Spoiler: Warning: Spoiler!



C0 (zero) is the C-state where the core is executing instructions.

C1 is when the core executed a "halt" instruction. The clock for the core will be stopped until it gets woken up by an interrupt signal coming in.

C3 will stop the clock on more parts surrounding the core.

C6 will cut off power. Data inside the cores has to be saved and later restored.

If the core is in C1 for a while, it automatically goes into C3, shuts off power to the core and more parts surrounding it with C6. That happens without Windows having to actively do any core parking or anything else.

The C1E feature makes it so the clock speed for the CPU gets reduced when all cores are in C1 (or C3, C6). On a CPU running at stock, that will reduce the voltage for VCore because clock speed is tied to that through the voltages changing through the CPU's VID table. When C1E is enabled and a core gets an interrupt signal and starts executing code again, it will then work at 1600 MHz for a while. If it finishes processing that code and goes back to C1 fast enough, the CPU might never ramp up to full clock speed.

There's also C-states for the whole CPU package. The rules for that are that all cores must be in at least that C-state. So if one core is doing something and is in C0, the package is in C0 even if several other cores are in C6 or something.



*About the actual settings in the BIOS:*

C1E does power saving because it causes an idle Windows machine to often run at 1600 MHz and using lower VCore at stock or with offset overclocking. This is completely automatic, Windows has no hand in it.

The EIST feature has a similar idea about running the desktop at 1600 MHz when idle, but it is done through Windows managing things and explicitly setting the clock speed. It's not automatically done by the CPU like the C1E stuff.

If you have the C3/C6 feature enabled in the BIOS, that will cause power to be cut completely in the core and around the core when those parts are asleep. If it's not enabled, everything still gets fed power even when clocks are stopped.

Haswell has extra features.









If you are interested in what's going on in real time, you can look at what's happening in your CPU with "RealTemp TI". The program can show the C-states and it can show VID. It looks like this: http://www.overclock.net/t/1330144/realtemp-t-i-edition


----------



## spin5000

Thank you


----------



## tp4tissue

Quote:


> Originally Posted by *r0cawearz*
> 
> for me, leaving the c states off gives me more stable voltages. i can't run x264 for more than a couple of minutes with cstates on, but with them off, i can go for much longer


cstates off = Cpu Viagra ???.


----------



## fateswarm

It's not certain it does anything, but it's a standard procedure to setup with them off to make sure they're not interfering.


----------



## tp4tissue

Quote:


> Originally Posted by *fateswarm*
> 
> It's not certain it does anything, but it's a standard procedure to setup with them off to make sure they're not interfering.


Rule #1 to overclocking.. turn off all motherboard features not in use..


----------



## prescotter

But it depends on your idea/vision if the C states are used or not.

Im runing Offset voltage on Sandy Bridge, All C States enabled and Enhanced SpeedStep enabled.

Otherwhise i would never be able to run 1.56-1.58v constantly on my CPU. Now i only see 1.45v+ under higher CPU Loads.
(Offcourse i would be able, but why run 1.56v when running idle?)

Perhaps my CPU would have died long ago if it werent for Offset/C States


----------



## tp4tissue

Quote:


> Originally Posted by *prescotter*
> 
> But it depends on your idea/vision if the C states are used or not.
> 
> Im runing Offset voltage on Sandy Bridge, All C States enabled and Enhanced SpeedStep enabled.
> 
> Otherwhise i would never be able to run 1.56-1.58v constantly on my CPU. Now i only see 1.45v+ under higher CPU Loads.
> (Offcourse i would be able, but why run 1.56v when running idle?)
> 
> Perhaps my CPU would have died long ago if it werent for Offset/C States


eist takes care of the idle issue


----------



## GeneO

Quote:


> Originally Posted by *tp4tissue*
> 
> eist takes care of the idle issue


And c1e if I recall correctly. If I remember, with Sandy and only EIST, the frequencies are lowered, but not the voltage, With C1E also , the voltage too. But maybe I misremember


----------



## jasjeet

Quote:


> Originally Posted by *GeneO*
> 
> And c1e if I recall correctly. If I remember, with Sandy and only EIST, the frequencies are lowered, but not the voltage, With C1E also , the voltage too. But maybe I misremember


Yes you need EIST and C1E enabled for both VID and Frequency to scale.


----------



## Luciferxy

Not for me, EIST & windows power plan are enough to reduce the cpu freq & VID. I'm using fixed vcore though as mobo don't have the off-set voltage option.


----------



## jasjeet

Fixed vcore on IB and getting a Vcore drop at idle? Hmmm not sure about that. Just double check the config for us.
Im using offset, EIST, C1E. Im sure with fixed no matter what you do the Vcore doesnt drop.


----------



## fateswarm

But can you reduce your voltage to 0.012v?


----------



## Agiel

in the afternoon i'll check mi vcore voltages, i don't remember voltages above 1.0v ... like i sayd i have to check when i get to home ...


----------



## tp4tissue

Quote:


> Originally Posted by *jasjeet*
> 
> Yes you need EIST and C1E enabled for both VID and Frequency to scale.


you don't need c1e

the voltage will still scale, when the core hits 1600


----------



## jasjeet

Quote:


> Originally Posted by *tp4tissue*
> 
> you don't need c1e
> 
> the voltage will still scale, when the core hits 1600


With fixed or offset Vcore?
And you get less intermediary steps with this configuration, which leads to reduced latency i guess.


----------



## Luciferxy

Quote:


> Originally Posted by *jasjeet*
> 
> Fixed vcore on IB and getting a Vcore drop at idle? Hmmm not sure about that. Just double check the config for us.
> Im using offset, EIST, C1E. Im sure with fixed no matter what you do the Vcore doesnt drop.


ofc the Vcore doesn't drop. But VID still drops (perhaps due to my mobo doesn't have off-set voltage).
Some pics :

C6, EIST & Win High Performance

see those valleys ? it'll stay there when gaming even with high performance power plan.
I don't like those fluctuations.

All C state OFF, EIST & Win High Performance


C6, EIST & Win Power Saver (min 46%, Max 60%)


All C state OFF, EIST & Win Power Saver (min 46%, Max 60%)


The differences with C6 & C state OFF-with EIST, are the more uniform temperature when *idle* & a bit lower VID with C6
But somehow with C6 enable, Vcore is slightly higher (1.152V) compare with C sate disable (1.144V).
For all the above condition is using Vcore set in BIOS 1.165V with Vdroop 37.5%


----------



## Agiel

why i can't get my numbers like that ?? i never get 3.8GHz all cpu shows is 3.791Mgz, and when i open Task Manager somethins it scales to 4.07Ghz is that normal ??


----------



## jasjeet

Ok i should of clarified, i asked about VID because on an offset config the Vcore is reliant on the VID, but in a fixed vcore config it isnt. So the VID is still fluctuating due to the multiplier dropping in your setup, but as you've said (and i was meaning to say), the Vcore doesnt. When using fixed vcore the VID doesnt do anything (its purely informational). You can see that effect in the first pic, the VID drops and the multiplier drops, but the Vcore remains static, as the Vcore is not equal to the VID+/- Offset when using a fixed Vcore.

Some like to have a low Vcore when at a low frequency, for that you have to have C1E enabled, not just EIST. And this will give much lower idle temps (if you are the type who is concerned about this).

With C6 is enabled the BIOS may compensate Vcore to prevent crashes during transitional frequencies and VIDs.


----------



## michael-ocn

i7-875k

c1e (enhanced c1 state) - off
cstates - on
eist (speedstep) - on

idle - multi is 9x -> 1.4GHz
working - multi is 25x ->3.9GHz
voltage doesn't change much between idle and full load, 1.288 vs 1.32'

here's a good explanation of powersaving modes
http://www.hardwaresecrets.com/article/Everything-You-Need-to-Know-About-the-CPU-C-States-Power-Saving-Modes/611/1


----------



## GeneO

Quote:


> Originally Posted by *Luciferxy*
> 
> Not for me, EIST & windows power plan are enough to reduce the cpu freq & VID. I'm using fixed vcore though as mobo don't have the off-set voltage option.


Was talking about Sandy, not Ivy.


----------



## Agiel

at the end i had to leave all in auto, is better auto than enabled ???


----------



## GeneO

Quote:


> Originally Posted by *Agiel*
> 
> at the end i had to leave all in auto, is better auto than enabled ???


Is this is Haswell? If so, auto may have the C6 and C7 disabled, Some MB manufacturers are playing it safe because some older power supplied can't handle the low power of these states.


----------



## jasjeet

Here were my results

All C States off Windows 100% Minimum CPU Speed


C1E only, Balanced Performance plan (5% Minimum CPU Speed)


C1E, C3 and C6, Balanced Performance plan (5% Minimum CPU Speed)


C1E, C3 and C6, Balanced Performance plan (100% Minimum CPU Speed)


So a 2MB/s 4k read speed increase, that is 12% increase. Too marginal to make a difference. heck i cant tell the difference using my Crucial M4 which has 29MB/s 4k random read.


----------



## one80

I tend to leave all the C-states enabled/on (i.e. default)...


----------



## Zero4549

Don't pay for power. Have excellent cooling. Answer should be obvious.


----------



## prescotter

Quote:


> Originally Posted by *tp4tissue*
> 
> eist takes care of the idle issue


I beleave the C6 state also helps in reducing Idle voltage on low work loads, it least it enables more inbetween steps then only 1.6Ghz and 5.0Ghz


----------



## Agiel

Quote:


> Originally Posted by *GeneO*
> 
> Is this is Haswell? If so, auto may have the C6 and C7 disabled, Some MB manufacturers are playing it safe because some older power supplied can't handle the low power of these states.


nop, im on ivi's ... Core i5 3570K


----------



## Agiel

do any one can help me ??

i have a GIGABYTE B75M-HD3 mobo, with a core i5 3570k, and 2x4GB Corsair Vengeance 1600Mhz, 9-9-9-24, i want to know if i can chance the memory latency to improve speed ...


----------



## Agiel

so with no oc, i disable C6 and C7 ? and leave EIST be ? for more stability ??


----------



## Wallboy

Sorry for the slightly old bump, but I noticed none of these different tests mentioned if they were using Dynamic Storage Accelerator Enabled or not. Apparently with this enabled in the BIOS, this fixes the latency issues with SSDs when C-States are enabled. Can anyone confirm?


----------



## GeneO

Quote:


> Originally Posted by *Wallboy*
> 
> Sorry for the slightly old bump, but I noticed none of these different tests mentioned if they were using Dynamic Storage Accelerator Enabled or not. Apparently with this enabled in the BIOS, this fixes the latency issues with SSDs when C-States are enabled. Can anyone confirm?


In manual mode, all it really does is allow you to enable or disable the c-states from the Intel RST control panel in windows, depending on the profile you select. I did not find auto useful at all - even though I had balanced power savings set, auto disabled all c-states at idle. Go ahead and play with it and monitor the C-states with something like realtemp. Basically lets you enable./disable c-states through windows, nothing dynamic about it as far as I can see.


----------



## opt33

The dynamic storage accelerator in the bios will improve but not eliminate the SSD latency induced by using C states, at least on my setup.

For example, on my crucial mx200 (after my 6 month old sandisk extreme pro bit the dust):

C states enabled, dynamic storage accelerator disabled in bios, then 4k random read in AS SSD = 26, overall score 1046.
C states enabled, dynamic storage accelerator Enabled in bios, then 4k random read in AS SSD = 30, overall score 1065.
C states disabled, which removes dsa from the bios (ie auto disabled and gone from view), then 4k= 33, overall score 1100.

So DSA helps with latency on my setup, but doesnt eliminate it. The same occurred with my sandisk extreme pro (rip).

But since I use manual vcore, all c states off, and high performance in windows, DSA is not applicable. But I would enable it on my laptop, where saving small amounts of power with c states makes sense to me.


----------



## buendia

I have disabled C6 C7 state on my Haswell i5 because of stability issues when coming out of sleep or hibernation which is related to my PSU because I believe it doesn't support such low power state and Windows would almost always BSOD. Since I disabled it, no issues.


----------



## error-id10t

Quote:


> Originally Posted by *opt33*
> 
> The dynamic storage accelerator in the bios will improve but not eliminate the SSD latency induced by using C states, at least on my setup.


Out of curiosity, have you checked the C states when you play around with DSA? The reason I ask is because when I was playing with it ages ago now, it itself changes the C states or rather what C states are allowed. If you have all C states enabled and flick it to power mode (whatever it is, forgot as I don't use it anymore) it removes disables C states. So I found it useless from that perspective.


----------



## opt33

Quote:


> Originally Posted by *error-id10t*
> 
> Out of curiosity, have you checked the C states when you play around with DSA? The reason I ask is because when I was playing with it ages ago now, it itself changes the C states or rather what C states are allowed. If you have all C states enabled and flick it to power mode (whatever it is, forgot as I don't use it anymore) it removes disables C states. So I found it useless from that perspective.


Others have tested that is disables some of the deeper sleep states, never tested myself, but the mhz and vcore will still drop to low values with DSA enabled so some power savings are still clearly enabled. And it makes sense that it does just that, because C6/C7 enabled only doesnt induce much latency. It is the deeper states that cause the latency...which means it makes as much sense to just use the C states in the bios that dont cause latency, as it does to use DSA. But I dont play with them much, sense I wont every use any power savings on a desktop...other than sleep mode when Im not using it.


----------



## spin5000

I never had issues with disabling c-states with my 2500k and my 4930k but they're (c-states) driving me insane on my 5930k...

I need to disable C states or else I get freezing/lock-up with an annoying buzz/squeel in Battlefield 4. However, everything else is stable with C-States enabled, and I mean everything: Prime95, Wprime, HyperPi, ASUS Relbench tests and the stress, Aida benchmarks and stress, Passmark Performance Test, and same with my memory, plus HCI Memtest and the newest version of GoldMem...

Here is where it gets really weird: *with C-States disabled, I seem to get very low single-threaded performance*. For example:

ASUS RealBench v2.41 Image Editing
C-States On: 65 sec
C-States Off: 85 sec

Passmark Performance Test, CPU Single threaded Test:
C-States On: 17,300
C-States Off: 16,300

Cinebench OpenGL:
C-States On: 190
C-States Off: 88

Cinebench CPU (Single Core)
C-States On: 175
C-States Off: 123

Cinebench MP Ratio
C-States On: 7.6
C-States Off: 10.6

NOTE: High performance mode in Windows is always selected with min processor speed at 100%. HWmonitor always reports the cores at 4.5GHz so nothing seems to be downclocking/throttling. Temps are in the low 60s to low 70s.

On top of that, my load and idle temps are both around 7-10 degrees hotter when C-states are disabled, even during identical loads/frequencies/voltages, etc. I never had this issue either with my 2500k or 4930k. My 4930k idled at 20 C even with c-states off as long as the vcore and frequencies all dropped to my idle settings.

So I'm damned if I do and damned if I don't with Haswell. Something isn't right here and I don't know what to do.


----------



## unclewebb

Can you try running RealTemp GT.

http://www.techpowerup.com/downloads/2089/real-temp-3-70/

If all of your C States are disabled, it should show a steady 45.0 multiplier when lightly loaded. If any C States are enabled such as C1E, C3, C6, C7; the reported multiplier will wander at idle. This is one of the few programs that will give you any indication when C States are being used.

There is another version of RealTemp but it doesn't fully support the 6 core CPUs. The T|I version will show you what C States your CPU is using. opt33 and error-id10t have used this software to learn more about C States. There are both individual core C States as well as package C States. When you have C States enabled, it would be interesting to see exactly which C States your bios has enabled. The info will look something like this.

http://i.imgur.com/PiuhBEE.png

RealTemp T|I Edition
https://www.sendspace.com/file/55yvry

Definitely something weird going on. It sounds like the bios or perhaps Windows is not setting something up correctly.


----------



## spin5000

Sweet, I'll try RealTemp GT.

BTW, here are the 3 c-state options in my ASRock X99X Killer MB

My motherboard's C-state options:

1. Package C State Support (select 1):
C0/C1
C6 (retention)
C6 (non-retention)

2. C3 (select 1):
Enable
Disable

3. C6 (select 1):
Enable
Disable

4. Enhanced Halt State (C1E) (select 1):
Auto
Enabled
Disabled

The motherboard defaults to:
C0/C1
C3-Disabled
C6-Enabled
Auto

And the MB's 4.2GHz+ presets have them set to:
C6 (non-retention)
C3-Disabled
C6-Enabled
Auto

So I'm guessing "C6 (non-retention)" is therefore better in an overclocked setup than "C0/C1" is?


----------



## GeneO

Cs is the next to deepest (deepest is C7) and takes longer to come out of than C1 or C3. So no C0states should give you the best performance, C1E, the next t best, and C1E + C3 the next, etc. The higher the number in the C state, the deeper the power savings mode and the longer it takes to come out of the low power c-state.

Those are a weird set of defaults If you ask me.


----------



## d0mini

All enabled. Power saving with little to no performance impact.


----------



## Wirerat

Quote:


> Originally Posted by *d0mini*
> 
> All enabled. Power saving with little to no performance impact.


same here. On all 4 haswell machines.


----------



## raidflex

You can just set Windows 8.1 to high performance power mode when you need it. This completely negates any "latency" issues with C states. Lower heat and energy usage is also helpful. With a cost of over 20C/kwH where i live, this can save me a lot of money when the system is idle. You know its expensive when your electric bill is more then your gas heating bill in the coldest months.


----------



## spin5000

With C-states on I consistently get single threaded scores in ASUS RealBench that are two seconds slower than with C-States off.

I think leaving C-State packages enabled (either "C0/C1", "C6 non retention", or "C6 retention") but disabling C-States (C6, C3) resulted in the same 2-second faster scores.

Having said that, in Passmark Performance Test, all CPU and memory tests are pretty much the same EXCEPT 2: The prime numbers CPU test, and the unthreaded (or was it uncached?) memory read test which consistently scores as high as 5% faster with C-States ENABLED.

How does that make any sense? And why does it happen in only 2 very specific tests?


----------



## softskiller

I made a thread with the fallowing a while ago, but noone replied. So I post it here. Maybe someone else notices that the settings for the single states in the BIOS matter and just to Enable all is not enough?
Quote:


> Well I don't really understand the C-States of my Asrock B85M Board with latest BIOS and Haswell Xeon E3-1231 v3 CPU.
> 
> BIOS says "Enable CPU C States Support for power saving. It is recommended to keep C3, C6 and C7 all enabled for better power saving"
> 
> I use tools like ThrottleStop or RealTemp TI to read out the used C-States over time under various loads.
> 
> If C3 Enabled, C6 Enabled, C7 Enabled: only C7 is used.
> 
> If C3 Enabled, C6 Enabled, C7 Auto: only C6 is used.
> 
> If C3 Auto, C6 Auto, C7 Auto: only C3 is used.
> 
> If C3 Auto, C6 Enabled, C7 Auto: combination of C3 and C6 is used.
> 
> If C3 Auto, C6 Auto, C7 Enabled: only C3 and C7 are used but no C6.
> 
> If C3 Auto, C6 Enabled, C7 Enabled: still only C3 and C7 are used.
> 
> If C3 Auto, C6 Auto, C7 Auto: only C3 is used.
> 
> So it seems: C6 or C7 are only used when set to Enabled and only the highest Enabled one is used - never C6 AND C7.
> C3 is only used in combination with C6 or C7 when set to auto but not when set to Enabled.
> When C6 and C7 are set to Auto Asrock will not use them at all, even when system is idle.
> 
> The goal should be that a combination of C-States is used depending on the load of the system for a good balance of energy saving and processing responsiveness.
> 
> Only to use C7 with highest latency even under heavy load like gaming is not perfect. Other faster C-states like C3 must not get ignored and are there for a reason.
> 
> I wonder if I should only use C3 or a combination of C3 with C6 OR C7, while C3 with C6 AND C7 is not possible.
> 
> (Nothing overclocked)


----------



## GeneO

C7 and C6 Auto must mean disabled
C3 Auto must mean enabled

C7 is a slightly lower power state than C7, but the behave almost identically. I imagine windows finds out whether C7 is available and uses it if so, otherwise it uses C6.

Also with all 3 enables and the system mostly idle, you will only see the deeper states.

I would have expected your case 2 and 4 to be the same.


----------



## ucode

Note that there are core C-states and package C-states. For example if a processor wishes to use the C1E package state then all core states must be C1 or higher, IOW no cores should be in C0 (active state).

Core C-states are initiated by the OS. Windows typically uses three C-states, C1, C2 and C3 however these should not be confused with the processor C-states. For instance Windows C1 may map to core C1 while Windows C2 may map to core C3 and Windows C3 may map to core C6. C-States may be entirely be disabled from the OS, BIOS has no control over core C1 state which is a halt state.

Core states may also be activated by 3rd party software. Here's an example of using core C7 on the first core, core C6 on the second core and Core C3 on the third core and core C7 again on the fourth core.










Note that the highest package C-state in this case is package state C3 due to core C-state C3 on the third core. If instead core 3 were core C6 then the package could be able to resolve to package state C6.

Package C7 flushes the L3 cache and would give IMHO horrible latency, not something to be interested in on a desktop as CPU package power should already be fairly low if in C6 for a fair amount of time while idle. More of something for laptops requiring battery savings with C8, C9 and C10 package states also available on the later models.

Hope that helps.


----------



## Sptz

I have an Asus z97 Pro with an i5 4690K. Since I got it, the default BIOS settings are with everything disabled I believe.

I decided to turn on C1E and C3, EIST is also ON, Minimum Processor State in Windows is 100% so it's remaining that idle at the Turbo frequency. Would this wield voltage savings or not really?


----------



## Prophet4NO1

Quote:


> Originally Posted by *Sptz*
> 
> I have an Asus z97 Pro with an i5 4690K. Since I got it, the default BIOS settings are with everything disabled I believe.
> 
> I decided to turn on C1E and C3, EIST is also ON, Minimum Processor State in Windows is 100% so it's remaining that idle at the Turbo frequency. Would this wield voltage savings or not really?


Every motherboard deafults to C-states on. At least since the feature appeared.

If they are on and you force 100% speed all the time in windows the voltage will not drop. Clocks and voltage will stay at what ever they are set to run at with max turbo.


----------



## Sptz

Yes, you're right. After testing, I think it automatically enables C1E and C3 but not C6 and C7.

After changing the minimum processor state in Windows it started to fluctuate now, which is what I wanted to be honest, I didn't think there was a need, IMO, to have the CPU running at full 100% of the time.

BTW, I have an EVGA P2 850w and it doesn't state if it's C6/C7 ready anywhere on their site, only for the G2 version and P2 1000w.

Does anyone know if this one can be used for it?

Thanks


----------



## GeneO

Quote:


> Originally Posted by *Sptz*
> 
> Yes, you're right. After testing, I think it automatically enables C1E and C3 but not C6 and C7.
> 
> After changing the minimum processor state in Windows it started to fluctuate now, which is what I wanted to be honest, I didn't think there was a need, IMO, to have the CPU running at full 100% of the time.
> 
> BTW, I have an EVGA P2 850w and it doesn't state if it's C6/C7 ready anywhere on their site, only for the G2 version and P2 1000w.
> 
> Does anyone know if this one can be used for it?
> 
> Thanks


They don't have c6 and c7 on by default because recent (haswell +) processors support new low power C6 and C7 that some older power supplies are not compatible with..


----------



## Sptz

My PSU does support it. I turned on both C6 and C7s and didn't see any difference in voltage usage. Realtemp TI does show C7 fully active but didn't make much of a difference to just having C1E and C3, which wasn't even being reported as being used in RealTemp TI btw, although I did see the clock going down to 800mhz and voltage to 0.7.

Anyone knows the deal?


----------



## deepor

What program do you use to look at the voltage? There are a lot of CPU-Z versions that report the voltage wrong for Haswell.


----------



## Sptz

Quote:


> Originally Posted by *deepor*
> 
> What program do you use to look at the voltage? There are a lot of CPU-Z versions that report the voltage wrong for Haswell.


I'm using the latest from the official website. Open HW Monitor is also reporting 0.88V. Could it be that these are just wrong?

Also, regarding Package C State Support, I have it on Auto, should I change to any of the numeric C-states? Or just leave it on auto?


----------



## unclewebb

Quote:


> Originally Posted by *Sptz*
> 
> Could it be that these are just wrong?


Intel CPUs use power gating. When a CPU core enters C6 or C7, it is disconnected from the voltage rail so it is getting zero volts. It is not unusual for individual cores to spend up to 99% of the time in C6 or C7 if it is available.

http://i.imgur.com/6UUUnaO.png

If you are using these deeper C States then you might as well ignore voltage monitoring software at idle because 99% of the time it is going to be wrong. Even if the voltage it reports is accurate for the other 1% of the time when the cores are active, what's the point. Voltage data is useless because it ignores what the CPU cores are really doing.
Quote:


> Realtemp TI does show C7 fully active but didn't make much of a difference to just having C1E and C3


Is that statement based on the voltage readings in CPU-Z or HWMonitor? Try measuring power consumption at the wall. That is where you will see a difference between C1E, C3 and C7.

Monitoring software also shows power consumption data but these numbers are only an approximation. This data is not measured power consumption. It is a number calculated by the CPU to manage the Intel Turbo Boost feature. This number might not be very accurate when sitting at the desktop with the C States enabled.


----------



## Sptz

Quote:


> Originally Posted by *unclewebb*
> 
> Intel CPUs use power gating. When a CPU core enters C6 or C7, it is disconnected from the voltage rail so it is getting zero volts. It is not unusual for individual cores to spend up to 99% of the time in C6 or C7 if it is available.
> 
> http://i.imgur.com/6UUUnaO.png
> 
> If you are using these deeper C States then you might as well ignore voltage monitoring software at idle because 99% of the time it is going to be wrong. Even if the voltage it reports is accurate for the other 1% of the time when the cores are active, what's the point. Voltage data is useless because it ignores what the CPU cores are really doing.
> Is that statement based on the voltage readings in CPU-Z or HWMonitor? Try measuring power consumption at the wall. That is where you will see a difference between C1E, C3 and C7.
> 
> Monitoring software also shows power consumption data but these numbers are only an approximation. This data is not measured power consumption. It is a number calculated by the CPU to manage the Intel Turbo Boost feature. This number might not be very accurate when sitting at the desktop with the C States enabled.


Thank you for your detailed reply!

I ended up disabling because I read somewhere that C6/C7 are only related to sleep/hibernation and also IGP? Is that true?
If it isn't and it does what you said then I'll re-enable it


----------



## Sptz

Would it also be worth to just have c6 and c7 enabled? Or have them all?

Sent from my D5803 using Tapatalk


----------



## deepor

Quote:


> Originally Posted by *Sptz*
> 
> Thank you for your detailed reply!
> 
> I ended up disabling because I read somewhere that C6/C7 are only related to sleep/hibernation and also IGP? Is that true?
> If it isn't and it does what you said then I'll re-enable it


This is not true. Someone might have misunderstood what "sleep" means in this case and then written something wrong.

The cores can do something that you could call sleep when there is nothing to do, then start working immediately when a signal from a device comes in and wakes them up. There's C-states for the individual cores, and "package" C-states for the whole CPU. Both are used a lot if they are enabled and you do boring things like web browsing. It's not just for putting your whole computer into standby.

If you look again at unclewebb's screenshot, what you see there means that each single core had been 99% sleeping in that "C7" state the last few moments as he took the screenshot, and the "package C6" stuff had also been used a lot at 87%.


----------



## unclewebb

Quote:


> Originally Posted by *Sptz*
> 
> I read somewhere that C6/C7 are only related to sleep/hibernation and also IGP?


Not true. If C6 and C7 are enabled, they will be used any time your CPU is not fully loaded which for most applications is going to be pretty much all of the time. Cores and threads will be constantly transitioning thousands of times per second from the C0 state when a task needs to be performed, back to C7 when there is nothing for the CPU to do. If you are gaming and only 2 cores are being utilized, the other 2 cores will be in one of these low power C States, saving power and reducing the core temperature of your CPU.

Intel included high performance timers in their CPUs so it is easy for monitoring software to accurately determine the percentage of time the cores and the CPU package are spending in these C States, without having to put any significant load on the CPU. This data is also an excellent way to keep track of how much crap is running on your system in the background. If you are not seeing 99% in C7, I would start looking through the Task Manager to find out why.

I recently installed Windows 10 on my laptop and found a Microsoft application called RuntimeBroker.exe that was stuck in some sort of loop. The upgrade was initially a miserable experience but after killing that one process, I can surf the net without my laptop burning through my lap because a CPU will run very cool when it is spending 99% of the time in C7.

On a desktop, saving some power and keeping the CPU temps down is not as important but even on a desktop, I still use the C States because it allows me to turn the CPU fan down to a bare minimum when lightly loaded so I can barely hear it.


----------



## Sptz

Aah I see! Thank you both.

So, should I just disable c1e and c3 since its going to favour and c7 anyway? Or would it be best to have just all of them and have it automatically juggle between what it wants?

Also, regarding package c-state, my asus has it on Auto, if I check the options it has c1,c3,c6,c7 and c7s. Should I select something there or leave it auto? I noticed on idle in Realtemp TI that the package section is always at zero with auto on.

I know on a desktop it's not totally necessary, it's mostly because of the electric bills and not keeping it at full speed when not doing anything as I think it's a waste.

Sent from my D5803 using Tapatalk


----------



## ladcrooks

for those that might have missed this Source



Conclusion

Both, voltage scaling and power draw are following an exponential growth. Depending on the CPU quality you should be able to hit 4.5 - 4.7 GHz at a healthy voltage and power draw with the current Skylake CPUs. However, at a certain point the increased frequency will draw too much power and the additional frequency will not pay off.
*
You also don't have to worry about any power saving options or voltage modes. My advice is to keep Speedstep enabled, disable C-States and use the Override voltage mode. This will be the easies way to overclock and you won't experience disadvantages over the other options.*

Consindering the 50 Watt I saved by undervolting my CPU, I strongly advice to avoid Auto CPU core voltages.


----------



## chrcoluk

thanks ladcrooks the power usage information is eye opening indeed, makes you wonder why c-states exist as the power savings seem abysmal. (my max cpu turbo is 4.3ghz in bios and using adaptive offset)

On the other hand the issue I have is if I disable c-states then idle cpu temps are 10C higher which I am not happy about so I tried to find an intermediate fix but there doesnt seem to be one.

All c-states off, eist on, min cpu set to 99% so min speed is cpu non turbo speed 3.4ghz - Windows cpu power settings work, 20us idle DPC latency. idle temps 38-45C (is summer)
All c-states on, eist on, min cpu set to 99% so min speed is cpu non turbo speed 3.4ghz - Windows cpu power settings work, 80us idle DPC latency, idle temps 30-35C
All c-states on, eist on, min cpu set to 5% so min speed is cpu non turbo speed 800mhz - Windows cpu power settings work, 80-300us idle DPC latency, idle temps 27-32C
c-state only C1E enabled, eist on, min cpu set to 99% so min speed is cpu non turbo speed 3.4ghz - Windows cpu power settings DO NOT work and cpu frequency seems to bottom 2.2ghz and max out at 3.4ghz, 50us idle DPC latency, idle temps 30-35C
c-state C1E and C3 enabled, eist on, min cpu set to 99% so min speed is cpu non turbo speed 3.4ghz - Windows cpu power settings work, 50us idle DPC latency, idle temps 30-35C

So keeping C6 and C7 off but allowing C3 and below, I have DPC latency mid way between the fully off and on, cpu temps are closer to C6/7 temps than off, so for now I am staying like this, but I feel its probably hurting performance a bit given the higher DPC latency. I also will keep min cpu set to 99% now as well.


----------



## Emmanuel

Based on my testing, I feel like I'm better served by EIST and C1E only enabled with the OS power profile set to 99% minimum. That way at idle the CPU runs at its stock frequency (3.6GHz) and low volts (0.85v), and then boosts to my overclock (4.3GHz) and high volts (1.355v) under load. But none of that 1.2GHz crap when I'm trying to get my PC to do stuff.


----------



## Squall Leonhart

the design of intels cpu's is such that having every core awake in single threaded scenario's will REDUCE performance.

do not disable C state tech, work your overclock around this feature.

Anyone who suggests disabling it has no idea what they are talking about and hasn't bothered reading the intel site.


----------



## Squall Leonhart

Quote:


> Originally Posted by *spin5000*
> 
> With C-states on I consistently get single threaded scores in ASUS RealBench that are two seconds slower than with C-States off.
> 
> I think leaving C-State packages enabled (either "C0/C1", "C6 non retention", or "C6 retention") but disabling C-States (C6, C3) resulted in the same 2-second faster scores.
> 
> Having said that, in Passmark Performance Test, all CPU and memory tests are pretty much the same EXCEPT 2: The prime numbers CPU test, and the unthreaded (or was it uncached?) memory read test which consistently scores as high as 5% faster with C-States ENABLED.
> 
> How does that make any sense? And why does it happen in only 2 very specific tests?


cores must share resources, when you turn cores off, there is less sharing going on and single threaded memory benchmarks will perform better.


----------



## Blameless

Quote:


> Originally Posted by *Squall Leonhart*
> 
> the design of intels cpu's is such that having every core awake in single threaded scenario's will REDUCE performance.
> 
> do not disable C state tech, work your overclock around this feature.
> 
> Anyone who suggests disabling it has no idea what they are talking about and hasn't bothered reading the intel site.


I disable c-states because it's easier to stabilize an OC without having to account for them.

I have also never seen the reduction in single threaded performance you describe.
Quote:


> Originally Posted by *Squall Leonhart*
> 
> cores must share resources, when you turn cores off, there is less sharing going on and single threaded memory benchmarks will perform better.


This is not true. An active core with nothing scheduled to it doesn't harm performance in the slightest for anything else. With nothing scheduled, there are no resources being used.


----------



## Squall Leonhart

Quote:


> Originally Posted by *Blameless*
> 
> I disable c-states because it's easier to stabilize an OC without having to account for them.
> 
> I have also never seen the reduction in single threaded performance you describe.


Then you're not looking properly.

https://software.intel.com/en-us/forums/software-tuning-performance-optimization-platform-monitoring/topic/535130
https://forums.aida64.com/topic/292-c-state-tech-disabled-negatively-affects-memory-bandwidth-tests/
http://www.tomshardware.com/forum/350661-28-states-influency-questions-improve-performance-2600

There are even posts in this very forum stating that they get better single threaded performance with c states enabled vs pushing higher clocks.
Quote:


> This is not true. An active core with nothing scheduled to it doesn't harm performance in the slightest for anything else. With nothing scheduled, there are no resources being used.


In a perfect world, this would be the case, but because fully awake but underutilised cores are preferred by the windows scheduler for kernel and driver activities, there is never a fully inactive core on modern operating systems.
By allowing the cores to sleep, these tasks are kept on un-slept cores which reduces resource contention in the cache and memory as they are usually handled in the hyperthreads.

if you need to disable cpu features for your overclock to be stable, then it just clearly and simply isn't stable at all.


----------



## Ding Chavez

According to this article disabling C states gives a boost for gaming. In GTA V the boost is quite large. I disabled mine. Idle temp went up by about 2c. Ran my Phenom 965 for 5 years at constant GHz and volts, no problems.

http://www.dungeoner.com/en/overclocking-and-intels-power-management-settings-eist-c-states-turbo-boost/#perftest


----------



## Squall Leonhart

The results on those graphs is frankly - normal variation, and wouldn't even be noticed.

as for GTA5, the engine is frankly garbage and no two playthroughs are ever the same utilisation or performance wise.


----------



## Blameless

Quote:


> Originally Posted by *Squall Leonhart*
> 
> https://software.intel.com/en-us/forums/software-tuning-performance-optimization-platform-monitoring/topic/535130


The results here are part of a well known artifact of using LINPACK (and other highly optimized benchmarks/tasks where resource contention outweighs SMT's advantages) with HT enabled, not the C-states themselves.
Quote:


> Originally Posted by *Squall Leonhart*
> 
> https://forums.aida64.com/topic/292-c-state-tech-disabled-negatively-affects-memory-bandwidth-tests/


I cannot duplicate these results.
Quote:


> Originally Posted by *Squall Leonhart*
> 
> http://www.tomshardware.com/forum/350661-28-states-influency-questions-improve-performance-2600


This is on a stock part. C-states may well let a few cores reach higher turbo clocks in such a scenario.

This is not relevant to an OCed part that is running at maximum clocks on all cores, all the time.
Quote:


> Originally Posted by *Squall Leonhart*
> 
> There are even posts in this very forum stating that they get better single threaded performance with c states enabled vs pushing higher clocks.


And most of them are wrong. Either anomalies that are hard to reproduce, or which can be isolated to some other cause upon further investigation.
Quote:


> Originally Posted by *Squall Leonhart*
> 
> In a perfect world, this would be the case, but because fully awake but underutilised cores are preferred by the windows scheduler for kernel and driver activities, there is never a fully inactive core on modern operating systems.
> By allowing the cores to sleep, these tasks are kept on un-slept cores which reduces resource contention in the cache and memory as they are usually handled in the hyperthreads.


Don't need C-states to do this. Proper affinity is all that's required.
Quote:


> Originally Posted by *Squall Leonhart*
> 
> if you need to disable cpu features for your overclock to be stable, then it just clearly and simply isn't stable at all.


It's not practical for me to rigorously test all the possible intermediate combinations that enabling c-states and other power saving features can produce and potential instability during such states is meaningless if the CPU is never allowed to enter them.


----------



## Squall Leonhart

Quote:


> Originally Posted by *Blameless*
> 
> I cannot duplicate these results.


not surprising, since aida64's memory test is no longer single threaded.

Quote:


> Don't need C-states to do this. Proper affinity is all that's required.


kernel scheduling doesn't take affinity into account, it see's a core it uses it.

Quote:


> is meaningless if the CPU is never allowed to enter them.


A meritable case for disabling C states.


----------



## Blameless

Quote:


> Originally Posted by *Squall Leonhart*
> 
> not surprising, since aida64's memory test is no longer single threaded.


Even in single threaded tests (MaxxMem, SuperPI, etc) I can't produce different results on basis of C-states/EIST enabled.
Quote:


> Originally Posted by *Squall Leonhart*
> 
> kernel scheduling doesn't take affinity into account, it see's a core it uses it.


Windows doesn't schedule kernel loads to logical cores that are already significantly utilized if there are free cores and most patched versions of Windows going back to XP/Server 2003 seem to be HT aware.

If anything, C-states would be _increasing_ resource contention by not waking up cores to schedule kernel loads to them and would assign them to cores already in use.


----------



## Ding Chavez

Quote:


> Originally Posted by *Squall Leonhart*
> 
> The results on those graphs is frankly - normal variation, and wouldn't even be noticed.
> 
> as for GTA5, the engine is frankly garbage and no two playthroughs are ever the same utilisation or performance wise.


The min frame rate in GTA V increased from 26 to 30 an increase of 15%, avg frame rate also increased.

Earlier in the thread it was shown disabling C states increased SSD performance.

Evidence clearly shows there may be a benefit turning it off, but you seem to ignore anything you don't like fine. Show some actual evidence of the benefit of C states, like power consumption or whatever, I'd be interested to see... On or off I'm not sure I care much lol.


----------



## spin5000

Quote:


> Originally Posted by *Squall Leonhart*
> 
> cores must share resources, when you turn cores off, there is less sharing going on and single threaded memory benchmarks will perform better.


OK but how are some tests faster with C-States on while some are faster with C-States off?
Quote:


> Originally Posted by *Ding Chavez*
> 
> Earlier in the thread it was shown disabling C states increased SSD performance.


That problem still exists??? Are you serious?


----------



## Blameless

Quote:


> Originally Posted by *spin5000*
> 
> OK but how are some tests faster with C-States on while some are faster with C-States off?


Poor thread scheduling by some apps, or excessively high load thresholds for waking up cores in some configurations.


----------



## Ding Chavez

Quote:


> Originally Posted by *spin5000*
> 
> Quote:
> 
> 
> 
> Originally Posted by *Squall Leonhart*
> 
> cores must share resources, when you turn cores off, there is less sharing going on and single threaded memory benchmarks will perform better.
> 
> 
> 
> OK but how are some tests faster with C-States on while some are faster with C-States off?
> Quote:
> 
> 
> 
> Originally Posted by *Ding Chavez*
> 
> Earlier in the thread it was shown disabling C states increased SSD performance.
> 
> Click to expand...
> 
> That problem still exists??? Are you serious?
Click to expand...

What problem... explain.

http://www.tweaktown.com/guides/6800/tweaktown-s-ultimate-windows-ssd-performance-installation-guide/index6.html


----------



## Prophet4NO1

I have been running my CPU at constant speed/voltage for a few years now. I have been turning C-states off pretty much since they arrived. Sometime in the P4 days if I remember correctly? They do some odd things from time to time. Granted I only do it on my desktop. Servers and laptops I leave C-states enabled since they run 24/7 and are not always under load. For me it's just one less thing to much around with when overclocking. Lock it down and let it ride. And it's never been a problem.


----------



## Bal3Wolf

i have used c states for years sometimes it takes some tweaking when overclocking to get them to play nice with a overclock but worth it in the long run with lower voltages and temps when not fully loaded.


----------



## spin5000

Quote:


> Originally Posted by *Ding Chavez*
> 
> What problem... explain.
> 
> http://www.tweaktown.com/guides/6800/tweaktown-s-ultimate-windows-ssd-performance-installation-guide/index6.html


According to that article, each of the following also increases SSD/storage performance: disabling EIST, setting loadline calibration to it's most extreme setting, enabling high BCLK mode.

Has anyone verified this? I'm a little skeptical but would love to know.


----------



## opt33

4K read/write usually takes ~ 15-30% performance hit when enabling C-states/EIST from increased latency, that has been around since intel x25m came out, and still applies on my samsung nvme and intel nvme drives, and 10+ other SSD's I have owned. There have been articles on it, and multiple threads in past, it is old news. Overclocking decreases latency, so will increase 4k read/write speed up to a point where remove any bottlenecks. I would use power savings on laptop to conserve battery power...just not on a desktop pc.

In fact here is testing on one of mine from 5 years ago with an old intel SSD drive


C states on, dynamic OC, look at 4k scores and latency


Here is test from 2+ years ago on my Sandisk extreme pro, only difference is C-states/eist off 1st


Same sandsisk extreme pro, C-states, eist on


And here is my current drive samsung 960 1tb nvme, 4.4ghz fixed OC, Cstates/eist disabled


And same samsung 960 1tb, 4.4ghz dynamic OC, Cstates/ EIST enabled, again performance hit to random 4k speeds, which is most important speed for typical computer use.


----------



## Blameless

Quote:


> Originally Posted by *spin5000*
> 
> According to that article, each of the following also increases SSD/storage performance: disabling EIST, setting loadline calibration to it's most extreme setting, enabling high BCLK mode.
> 
> Has anyone verified this? I'm a little skeptical but would love to know.


C-states actually alter the performance of the CPU, so some performance side-effects, especially at low loads, are plausible. Drive transfers are one of these cases, because they have very low CPU load, so won't cause clocks to rise, but even low loads can benefit from the lower latency and higher performance of higher clock speeds.

Loadline calibration and high BCLK mode should not affect anything at all with regards to performance, in and of themselves. If tests show they are, it's a fluke, or something else is going on.


----------



## Niobium

All my power saving features are on since I don't bother to overclock my 4790K anyway.

I also had them on too when I was still rocking 2500K @ 4.3GHz.


----------



## spin5000

Quote:


> Originally Posted by *Blameless*
> 
> C-states actually alter the performance of the CPU, so some performance side-effects, especially at low loads, are plausible. Drive transfers are one of these cases, because they have very low CPU load, so won't cause clocks to rise, but even low loads can benefit from the lower latency and higher performance of higher clock speeds.


OK but here's the thing. If Windows is set to High Performance (power plan) and with the CPU min speed and max speed both set to 100% (the default in High Performance mode if I remember correctly) then clocks rising shouldn't matter since all clocks should be at a constant 100% even if C-states, EIST, etc. are enabled. So how do some programs and/all SSDs run faster with C-States disabled if leaving C-States enabled (w/ Windows High Performance Power Plan) keeps the CPU at 100% frequency?

P.S. It seems that leaving Windows in High Performance mode while keeping C-States and EIST enabled keeps only my 4930K at 100% frequency, _not_ my 5930K. Something internal seems to be overriding Windows' Power Plan with my 5930K/X99 while WIndows' Power Plan seems to work perfectly - CPU frequency wise - with my 4930K/X79.


----------



## Blameless

I've noticed the same phenomena.

Even with the high performance plan and no throttling set in power management, EIST will still underclock the cores on my LGA-2011v3 parts to 1.2GHz when not sufficiently loaded.


----------



## opt33

Same platform variation here. On my old 4790k and mobo, using high performance in windows or disabling just C6, left SSD performance closer to normal, allowing use of some c states. In that one thread on here ? years back, the effect varied per mobo/cpu which Cstates could be used, the degree of effect, and whether high performance mitigated the latency.

On both the X99 boards I have used with 6850, each power savings feature simply increases latency more, and using 5% min processor (balanced) increases latency over high perf, but high perf doesnt prevent the increased latency of Cstates/eist, and allows my cpu to idle 1.2ghz. The increase latency of all add up to a significant effect, 25% slower random 4k read and 60% slower random 4k write.

Few years back I just said screw it and use high perf and disable all power savings


----------



## Arxontas

I have every single power saving feature enabled.

In addition, my CPU [email protected] 99% of the time, except when I am gaming.

I also sometimes disable TURBO BOOST even at stock through Real Temp 3.70 when I am just reading on the PC. All my case fans are switched to OFF except one intake except when gaming. To further enhance power savings, I use both OPTIMIZED PHASE and ACTIVE FREQUENCY power saving features of my Maximus mobo.

Absolutely no need to do so as power is cheap, but it's just fun to use a killawatt and find out how to optimize power savings even further.

Here's some KILLAWATT readings:

1. Everything switched off but power button on the power rail set to "ON": 2.1 Watts

2. Monitor & Speakers ON - PC Off: 44 Watts

3. PC on - Idle (browser on), Speakers on, Monitor on: 117-123 Watts (Only CPU fan and one intake fan working)

4. PC on - Idle, Speakers On, Monitor On, All Fans running at max (6 case fans + CPU fan): 136 Watts

4. Gaming - WoW Vanilla(@60FPS): 217 Watts (only CPU Fan + 1 intake fan working)

5. Gaming - GTAV (@60FPS): 460 Watts (all fans running at max speed)


----------



## IaVoR

C-States on AUTO
EIST Enabled

I only use windows power plans for when I need to game


----------



## Tom Brohanks

Hell yeah I use C-states. Power savings are great, keeps the CPU cooler, and it's not an issue under actual load. C-states have come a long way since the P4 days when they were not good.

You guys should really read in to what c state and p state changes exist with each Intel processor release.


----------



## Bigceeloc

I am going to be experimenting with these in BIOS to see how they run in my machine. I am wanting to try it out disabled and see if it helps my latency issus.


----------



## Avalar

Soooo I have all C-states disabled to reduce my mouse input lag on my system. Am I killing my motherboard/CPU...?


----------



## Zero4549

Quote:


> Originally Posted by *Avalar*
> 
> Soooo I have all C-states disabled to reduce my mouse input lag on my system. Am I killing my motherboard/CPU...?


No.

The only thing you're killing is your wallet from higher power bills. I've got machines running today that have been on 24/7, all power saving features disabled, with original hardware, overclocked, since 2005.

Unless you get unlucky with faulty parts or do something incredibly stupid, you'll retire your system due to simply being too outdated to be worth using long before you do any damage from disabled power saving features.


----------



## Bigceeloc

Does the High Performance Plan in Windows 10 or a variation of it disable the c states?


----------



## Bigceeloc

So far, disabled C States has reduced my stutter in games, I limited my C states in bios to C0/C1 and disabled enhanced C1. But I don't want to miss out on the power savings! Anyone know if windows power schemes influences C states?


----------



## mikeyy233

should i enable it on a 2600K ?


----------



## Bigceeloc

Give it a try Mikey! If it breaks something, you can always turn it off again, right?


----------



## mikeyy233

LOL whats that spoused to mean


----------



## opt33

When l disable all power savings on my overclocked cpu, it translates into about 30 watts saved per hour that my computer is awake (~8 hours). So it costs me $9.50 per year to disable all my power savings. Basically I am paying ten dollars per year to gain 20-30% faster SSD small file transfer speed, to me that is well worth it. If I were a company with 1000 computers, then power savings on cpu become important.

Putting my computer to sleep when not using it, saves 160 watts x 16 hours per day, or $98 dollars per year. Sleep mode, unlike power savings, doesnt negatively affect my computer use.


----------



## Bigceeloc

Quote:


> Originally Posted by *mikeyy233*
> 
> LOL whats that spoused to mean


Lol, I really don't think it will be a problem. CPUs that support it will support it while cpus that don't will ignore the bios setting.


----------



## chrcoluk

Quote:


> Originally Posted by *Squall Leonhart*
> 
> Then you're not looking properly.
> 
> https://software.intel.com/en-us/forums/software-tuning-performance-optimization-platform-monitoring/topic/535130
> https://forums.aida64.com/topic/292-c-state-tech-disabled-negatively-affects-memory-bandwidth-tests/
> http://www.tomshardware.com/forum/350661-28-states-influency-questions-improve-performance-2600
> 
> There are even posts in this very forum stating that they get better single threaded performance with c states enabled vs pushing higher clocks.
> In a perfect world, this would be the case, but because fully awake but underutilised cores are preferred by the windows scheduler for kernel and driver activities, there is never a fully inactive core on modern operating systems.
> By allowing the cores to sleep, these tasks are kept on un-slept cores which reduces resource contention in the cache and memory as they are usually handled in the hyperthreads.
> 
> if you need to disable cpu features for your overclock to be stable, then it just clearly and simply isn't stable at all.


I know the logic of what you saying, basically forcing single threaded stuff to stay on one core is more efficient as you dont get context switching and better cache hits on the core cache. I agree on that.

However

Reducing clocks does not speed up single threaded performance, in addition the windows cpu scheduler is kind of weird and can act weird when cpu cores are disabled, I did a lot of testing using a game called lightning returns, this game is single threaded and I tried a few tricks to see what happens when you reduce the cores available to it.

So in default configuration without me touching cpu affinity or core parking settings, the game rapidly moves its thread between the 4 cores in my system, and cpu usage will appear something like this for the 4 cores In brackets I put the kernel utilisation.

70% (34%)
20% (17%)
25% (23%)
18% (14%)

Note the total exceeds 100%, this is because of context switching overhead. The first core remains the highest reported load, looking at task manager, the bulk of utilisation on the other 3 cores is kernel based so context switches, most of the userland load is on core 0.

If I adjust the windows core parking settings to be agressive, then core 3 (fourth core) stays parked, core 2 flips between park states, and the first 2 cores stay on all the time., the cpu load on core 0 starts bouncing around more and is getting more bottlenecked evidence by the stuttery performance in game.

Likewise if I force lesser cores via cpu affinity settings the game performance drops. This didnt make sense to me but it is what happens.

If I reduce the affinity to one core, then all the kernel utilisation (context switching) vanishes and its clearly more efficient but sadly the game doesnt perform as well as letting it use all 4 cores.

I blame for the most part the poor windows cpu scheduler, on linux if something is single threaded it doesnt move between diff cores like on windows, it will stay on one core. On windows it seems if you try to force behaviour that windows isnt programmed for then you get a performance hit.

Cpu usage and kernel in brackets when cpu affinity forced to one core for game.

100% (1%)
1% (0%)
2%(0%)
0% (0%)


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## Bigceeloc

I like that explanation! Having more cores awake means less time waking up the cores also. But with the scheduling of activity on cores, there seems to be just enough of that overhead that hitches these games. It would be nice if games such as Lightning Returns latched onto a core and stuck with it, which would keep the core awake and ready for loads.


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## Symbfrk2

I did some tests and comparisons and decided to disable EIST while keeping C-States enabled. Because that's the only combination (at least on my 4790k stock) which yields best performance (~28 DPC + 990 scores AS SSD) while keeping power usage and temperatures low! Only 40c (summer time), vCore @ 0.24 and chews 3 watts. If I disable both I get slightly better performance (~15 DPC + 1010 scores on AS SSD) but the temperature increases by 12C, vCore stays @max 1.256v and power consumption is 28 watts. This is on windows 7. IMO the trade for such minor, probably unnoticeable difference isn't worth it.


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## Prophet4NO1

To be fair, that difference in power consumption will make almost no difference in the power bill unless you have crazy high costs. Hell, I don't even worry much about my router and file server that are on 24/7 with quad core Xeons in them. Also have a dual 775 Xeon system that runs 24/7. Same there. I just let them do their thing. Don't really notice on the bill.


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