# What does "Power Limit" do in MSI Afterburner?



## ploppercon

I have a Radeon 7850, and I tried the max overclock for my card which is 1050/1450 and I got a crash in Planetside 2 within minutes. I saw that other people were flawlessly getting these speeds so I guess that I have to adjust the power limit, but will this damage my card? I know overvolting will make the card degrade faster, but is this "Power Limit" setting similar / the same? Basically, will adjusting the power limit damage my card or make it degrade any faster, and will it help me achieve higher memory speeds?

Thanks in advance.


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## absoluteloki89

Normally your card has a set power that it is set to consume say 300 watts. The slider allows it to consume more power if it needs to in order to achieve higher overclocks.


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## ploppercon

But will it harm my card?


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## Dhalgren65

You should be safe.








There is also a power limit slider in CCC(scroll down).
Since the 6950 series I think-
I ALWAYS peg to +20% for stability.
I usually set profiles in AB,2d clocks at stock,3d oc'd to max with add'l voltage,w/+20 power limit.
The last time I forgot it I had a few crashes,once set to +20,solid/smooth.
You don't say what Mfg or model your card is-
MOST with adequate VRM cooling will see little or no "degradation",as far as I have heard/read,
even w/OC's & add'l volts.
I can't qoute real numbers,but I'd bet that fewer than 10% of ALL GPU's fail due to normal use of CCC/MSIAB for overclocking.
INSANE(30%+)OC's,Volts (like 1.325) & bad VRM cooling(not to mention volt mods)probably cause problems,but you should be fine...


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## Z Overlord

I remember some guy here said it makes your overclock less stable and I gotta agree, even a small OC will be unstable if this isn't set to 0, no matter what the voltage


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## 2002dunx

It simply allows the card to draw the maximum that ATI thinks reasonable, sure it may reduce the life by a day or two, but how many cards have you owned till death ? None of mine have died yet in four plus years of OC'ing at increased volts.

>40% OC with my XFX 7950 DD, at +20% power setting at stock volts. 1150 MHz will do for me.

dunx


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## vinton13

I'm reviving an oldish thread, with two questions. I just got a new card that opens this option on MSI Afterburner.

1.) How does this differ from voltage control?

2.) How would this cause instability?

Thanks.


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## brettjv

Quote:


> Originally Posted by *vinton13*
> 
> I'm reviving an oldish thread, with two questions. I just got a new card that opens this option on MSI Afterburner.
> 
> 1.) How does this differ from voltage control?
> 
> 2.) How would this cause instability?
> 
> Thanks.


It's quite different from voltage control. It's something more akin to 'wattage control'. Your card has some amount of 'juice' it's expected to run at, at a maximum. Let's say you have 2 x 6 -pin connectors on your card + the power from the motherboard. The max 'rated' wattage draw from each of these three connections is 75W, and you have 3, so the absolute max wattage draw that AMD is going to 'allow' your card to draw is 225W.

However, they likely 'expect' a card with this connector configuration to draw something like 175W. Lets call that wattage amount the card's TDP, for the sake of simplicity.

So, when your power limit is set at 100%, this means your card is 'limited' to it's TDP, and if whatEVER you're doing with the card is causes it to exceed a draw of 175W, the driver will start to downclock and downvolt the card in order to get it run within the expected power envelope designated by the power target slider and the TDP.

Raising the Power Target up simply allows for your card to draw more juice through it's three connectors without resorting to downclocking/volting. In the scenario I described, it's likely that whatever % value you have available over 100% is going to reflect the difference between TDP and 'max safe wattage draw', based on the connectors running to your card. If your card indeed had a TDP value of 175, it's likely that max power target would be 100% + (225-175)/175 * 100, or 128% maximum power target.

So, when you OC, and especially when you OV your card, you are obviously likely to increase the power draw of the card (depending of course on the intensity of the test, whether you have v-sync on, these types of things), and if you don't raise the power limit, it might well cause the card to downclock/downvolt when you don't want it to.

I've never heard that raising power target causes instability, and if it does, it's because something is 'broken' in terms of the driver or the application you're using to raise the target. If things were working correctly, the impact of raising the slider should only be as I described above, basically just allowing you to reach higher OC/OV w/o downclocking due to excessive power draw ... but all this of course assumes that your card is otherwise capable/stable at the OC/OV combination you're chosen ... raising the target shouldn't affect stability, just the point at which the card auto-downclocks to save energy


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## Wheezo

Wow, that explains it really well. Thanks brettjv.


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## vinton13

Thank you brettjv! Very informative! Virtual rep+


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## FtW 420

Quote:


> Originally Posted by *brettjv*
> 
> It's quite different from voltage control. It's something more akin to 'wattage control'. Your card has some amount of 'juice' it's expected to run at, at a maximum. Let's say you have 2 x 6 -pin connectors on your card + the power from the motherboard. The max 'rated' wattage draw from each of these three connections is 75W, and you have 3, so the absolute max wattage draw that AMD is going to 'allow' your card to draw is 225W.
> 
> However, they likely 'expect' a card with this connector configuration to draw something like 175W. Lets call that wattage amount the card's TDP, for the sake of simplicity.
> 
> So, when your power limit is set at 100%, this means your card is 'limited' to it's TDP, and if whatEVER you're doing with the card is causes it to exceed a draw of 175W, the driver will start to downclock and downvolt the card in order to get it run within the expected power envelope designated by the power target slider and the TDP.
> 
> Raising the Power Target up simply allows for your card to draw more juice through it's three connectors without resorting to downclocking/volting. In the scenario I described, it's likely that whatever % value you have available over 100% is going to reflect the difference between TDP and 'max safe wattage draw', based on the connectors running to your card. If your card indeed had a TDP value of 175, it's likely that max power target would be 100% + (225-175)/175 * 100, or 128% maximum power target.
> 
> So, when you OC, and especially when you OV your card, you are obviously likely to increase the power draw of the card (depending of course on the intensity of the test, whether you have v-sync on, these types of things), and if you don't raise the power limit, it might well cause the card to downclock/downvolt when you don't want it to.
> 
> I've never heard that raising power target causes instability, and if it does, it's because something is 'broken' in terms of the driver or the application you're using to raise the target. If things were working correctly, the impact of raising the slider should only be as I described above, basically just allowing you to reach higher OC/OV w/o downclocking due to excessive power draw ... but all this of course assumes that your card is otherwise capable/stable at the OC/OV combination you're chosen ... raising the target shouldn't affect stability, just the point at which the card auto-downclocks to save energy


The power target does seem to have some strange effects with some applications/gpu bios/drivers. When I got my 7970 I read quite a few posts where +20 was recommended for overclocking, although when running benchmarks I got higher clocks & scores with the power limit lower. 20% would crash where 5% would pass.
I am a bencher though & rarely game, so not sure if games & benchies behave differently with the power limit. My last time benching 3dmark 11 at 1600/1800 1.56V I was using 5% - 10%, no downclocking, downvolting or throttling.


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## Derpinheimer

I dont really see how the power limit would ever effect performance unless you're passing the line. I mean, if 5% is within bounds and 20% is within bounds, then neither should be doing anything differently... unless there is more to it, but I cant see why it would complicated.


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## cime89

I have a MSI nvidia GTX 750 Ti 2GB OC graphic card and in afterburner I noticed that when I play watch dogs power is going up to 117% even if the maximum value is set to 100%. Is this normal?


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## RipperLord

Literally just changes your TDP draw. e.g. My card is at 229w by default. If I were to put it on +20%, it would put it to ~275w
This doesn't damage the card but it does heat it up more, as it's during more power.


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## prescotter

Quote:


> Originally Posted by *FtW 420*
> 
> The power target does seem to have some strange effects with some applications/gpu bios/drivers. When I got my 7970 I read quite a few posts where +20 was recommended for overclocking, although when running benchmarks I got higher clocks & scores with the power limit lower. 20% would crash where 5% would pass.
> I am a bencher though & rarely game, so not sure if games & benchies behave differently with the power limit. My last time benching 3dmark 11 at 1600/1800 1.56V I was using 5% - 10%, no downclocking, downvolting or throttling.


It also depends how high the Manufacturer/Seller set the Base TDP. Example some cards may have 200W Base TDP + 20% = 240W powerdraw, while other cards may have Higher Base TDP.

My (reference) HD7970 on 1200mhz core 1.25v will downclock on default TDP + 20% power limit.

So i modified my bios to a Base TDP of 250W and power Slider to 50% resulting in a max allowable powerdraw of 375W.
Without this my Core will not stay on 1200mhz and starts to TDP-Throttle to 0.8v and variable clock speeds of 500-700Mhz

Now I dont need to set my Power Limit to the full 50% for 1.2Ghz core 1.25v, but i left some margin for when i go 1.38v vcore with Sapphire Trixx

If you read a bit in the HD7970 Bios Modding threads you will see there are lots of users who needed to modifiy their Base TDP and Power Limit % to achieve constant max clocks.

Edit: FtW 420 what kind of HD7970 do you have? Allot of non-reference / OC models allready have the BASE TDP set way higher, so you cant really compare Power Limit % from card to card.


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## cime89

My core clock shows constant 1150 MHz while playing watch dogs, temperature goes up to max 72 degree celzius, no more. However I have a problem with message 'Display Driver stopped working and recovered" every once a while. PC is brand new. It happens only when I start game, screen freezes with some strange pink dots or screen becomes black. Usually I can acces Task manager using Ctrl+Alt+Del but sometimes I have to restart PC. But there is no rule to this. Sometimes I play game without problems, everything works smooth but sometimes I have problem with freezing. If the game is loaded and nothing happens in few second then it wont happen during gameplay. I read so many threads about this issue and so many people have it but I tried every posible solution that I found and nothing. I used benchmark tool FurMark and let burn in test for about 20 minutes and everything worked perfect. Temp. was max 72 degrees celzius.

I know this is not the topic but I wanted to ask you guys if you know anything about it, I thought that power exceedes maximum which is 100% might be causing this problem.

My specs are:

MSI B75MA-E31

Intel i5 3350P 3.1 GHz

MSI nvidia GTX 750 Ti OC 2GB

8GB RAM Kingston HyperX 1600 MHz

PSU is 520W


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## daniel.hall_6379

ploppercon said:


> I have a Radeon 7850, and I tried the max overclock for my card which is 1050/1450 and I got a crash in Planetside 2 within minutes. I saw that other people were flawlessly getting these speeds so I guess that I have to adjust the power limit, but will this damage my card? I know overvolting will make the card degrade faster, but is this "Power Limit" setting similar / the same? Basically, will adjusting the power limit damage my card or make it degrade any faster, and will it help me achieve higher memory speeds?
> 
> Thanks in advance.


This may help someone out a bit further
MSI AFTERBURNER POWER LIMIT SLIDER doesnt work


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