# DDR2 Memory Speeds Explained



## durch

Hello all,

While reading through the forums, I often see a lack of understanding in how your computer calculates DDR2 memory speeds and what you can do to change it. It is my attempt to explain this in detail, as most people give one line answers and you can't possibly explain this in one sentence.

First, let me say that I don't know what the "accepted" term is for a lot of settings since so many people mix old Intel words (like FSB) with AMD features and likewise mix old AMD terms for DDR and socket 939 with newer, very different DDR2 memory and socket AM2. Also, every motherboard uses a different term adding to the confusion. So let me define the terms I'll be using.

a) reference clock - That number that starts at 200MHz and gets multiplied by the CPU multiplier to give you your "total CPU speed". It's what you increase to overclock your CPU.
b) total CPU speed - the total speed, example: 2200MHz for my X2 4200+ at stock
c) memory setting - i.e. DDR2 800, DDR2 667, DDR2 533, DDR2 400. Get the idea? Many people often call this the divider, but as you'll see that isn't really correct.

Here's the basic principle of your DDR2 memory's speed. It's calculated by taking the total CPU speed and dividing it by some number, the divider. This divider isn't chosen at random, the computer follows strict rules when choosing the divider. If you understand how it chooses it, you can control your overclock. Here's the equation written out:

Memory speed = (total CPU speed)/(divider)

So logic tells you that to adjust the memory's speed, you must adjust the "total CPU speed", the divider, or both! As you'll see, this can get complex for DDR2.

Open this chart in another window, it's VERY valuable and will help you understand what I write below:
LEARN THIS CHART. IT'S YOUR FRIEND.

Adjusting the "total CPU speed":
To do this, you either increase the reference clock from 200MHz to a higher number, change the multiplier, or both. However, what usually happens in overclocking, is you figure out that magical "total CPU speed" that your processor can handle at its default multiplier (which cannot be increased). But at that CPU multiplier, you're stuck with a high divider. People will lower their CPU multiplier to get a lower divider, but as you lower the CPU multiplier, your "total CPU speed" drops. Oh noes! So you jack up the reference clock to acheive the same product. So that's why increasing the reference clock has an indirect effect on increasing the memory's speed. It's really the "total CPU speed" that affects the memory's speed, but to acheive that speed with a lower multiplier you need a higher reference clock.

Adjusting the divider:
Everyone uses archaic terms like set a 1:1 divider. Show me an AM2 motherboard with DDR2 memory that has a CPU:memory ratio option in the BIOS and I'll give you a cookie







. As a noob learning to overclock a couple months ago I was like.... "huh?" everytime I heard someone say that, because I had no idea what they meant. I think when people say that, they're referring to the old 939 days where the reference clock was 200MHz (still is) AND the frequency of the memory was 200MHz (but 400MHz effectively since its DDR, or double data rate memory). So setting your memory to DDR 400 was setting it to operate at 200MHz just like the reference clock, or a 1:1 ratio. Those were the simple days when that's all you had to do. In today's world with DDR2 memory, the 1:1 ratio doesn't have much meaning.

Here's what effects the divider with DDR2 memory and AM2 sockets. The CPU multiplier, and what I call the "memory setting" (i.e. DDR2 800, 667, 533, 400). It's not really accurate to just say set the divider since two factors influence it, so several combinations will yield the same divider.

Let's say we hold one factor constant, the memory setting (put it at DDR2 800). With a CPU multiplier of 10 or below, the divider is 5. A multiplier of 11 or 12 gives a divider of 6. A multiplier of 13 or 14 gives a divider of 7. A multiplier of 15 or 16 gives a divider of 8. See a pattern?

What if we hold the CPU multiplier constant, say 10x. Well, at DDR2 800 you get a divider of 5, DDR2 667 the divider is 6, DDR2 533 the divider is 8, and DDR2 400 the divider is 10. Now if you both change the memory setting AND the multiplier, you can get all sorts of combinations. For example, a CPU multiplier of 12 at DDR2 800 gives a divider of 6, but so does a CPU multiplier of 10 at DDR2 667. You have to consider both factors.

LEARN THIS CHART. IT'S YOUR FRIEND.

One Last Point:
What confuses people the most is the underclocking of memory caused by DDR2 memory paired with an odd or fractional CPU multiplier. Here's what makes it so difficult: THE DIVIDER MUST BE A WHOLE NUMBER. Why is that a big deal? I'll explain in a minute, but first, the three rules your memory follows:

1) The divider must be a whole number.
2) ("total CPU frequency")/divider cannot exceed 400MHz for DDR2 800, 333MHz for DDR2 667, 267MHz for DDR2 533, or 200MHz for DDR2 400 *at the stock reference clock of 200MHz*.
3) When choosing a divider, the CPU chooses the smallest number that won't violate rules 1 or 2.

Let's take an easy combination. The X2 4400+ Windsor with a 200MHz reference clock and a 12x multiplier and the memory set to DDR2 800. 200 x 12 = 2400MHz, the stock speed. Remember, with the memory set to DDR2 800, it sets your divider to the *SMALLEST whole number that won't be greater than 400MHz*. 2400/6 = 400, all rules are met. Why not set the divider to 5? 2400/5 = 480, this violates rule 2. Why not set the divider to 7? Because 6 met conditions 1 and 2, and rule 3 says choose the smallest number that works. Easy enough I hope, and it results in your memory running at what you expect it to, 400MHz (800MHz effective).

Let's make it more complicated. Take the X2 4200+ Windsor with a 200MHz reference clock and an 11x multiplier with the memory set to DDR2 800. 200 x 11 = 2200MHz, the stock speed. Remember, with the memory set to DDR2 800, it sets your divider to the *SMALLEST whole number that won't be greater than 400MHz*. What happens if we set the divider at 5? 2200/5 = 440MHz. This violates rule 2, so the divider stays at 6. Even though the 4200+ runs at 2200MHz and the 4400+ runs at 2400MHz, they use the same divider. Let's look at what effect this has on the memory's speed. 2200/6 = 366.67MHz (733MHz effective). Woah! Even though you set the memory to DDR2 800, it's being underclocked to DDR2 733. This is because ideally, the divider should be 5.5 (2200/5.5 = 400) but that violates rule 1. This is true for all odd CPU multipliers and DDR2 memory, your memory will be underclocked!

Think about it, only multiples of "total CPU speeds" of 400 work out evenly. i.e. 2000MHz, 2400MHz, 2800MHz, etc. If you have a CPU speed like 1800MHz, 2200MHz, 2600MHz, etc then you can't divide by a whole number and get 400, so your memory is being underclocked.

This means that the even multipliers are advantageous if you have good RAM, as they start your RAM at 400MHz instead of some underclocked value. 10x and 12x are very popular for overclockers with good memory because you can get more from your memory.

Remember though, this divider is chosen based on those three rules when the reference clock is at 200MHz. The divider stays the same as the reference clock is increased. However, as clearly shown above, as the reference clock goes up the "total CPU speed" goes up. So if the divider stays the same, but the "total CPU speed" goes up, then as you raise the reference clock to overclock your CPU you'll be indirectly raising the speed of your memory.

I hope this LENGTHY explanation helps some people. Plz correct me if anything is wrong and feel free to add/clarify anything!

EDIT: I changed "HTT" to the more correct term "reference clock". Please note that many of the responses use the term "HTT" and they are referring to the reference clock.


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## CWell1337

Looks good to me. Lengthy but accurate. Just keep in mind my charts you've linked are for AMD DDR2 speeds/dividers etc.

Overall a good job though.


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## Emmanuel

Read half of it, really interresting, however I think I someone made a FAQ about it before, but it still deserves the REP.


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## namehater

splendid write-up! +rep!


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## durch

Quote:


Originally Posted by *Emmanuel* 
Read half of it, really interresting, however I think I someone made a FAQ about it before, but it still deserves the REP.

Yea there's some FAQ's on the issue but they didn't make much sense to me when I was starting out, I was hoping this would benefit the people who are new to overclocking by giving more detail, examples, and using more descriptive terms (or at least define the terms) instead of technical ones. I know when I first started learning a few months ago it was very hard to understand all the technical terms, especially since everyone calls things like the HTT, divider, etc something different.


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## The Duke

Sticky Time


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## michinmuri

Love it! I will use this to help and hopefully my ancient math skills will come back to me so I can apply this. Rep for you!


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## Notorious

Great great article, i understand more, but i hope i don't understood wrongly haha.

Ok so what's the main purpose of this information and chart? :x is it so that when overclocking, we can get the desired RAM clock speed? And because usually when people OC their system they forget about the divider and their RAM get underclocked? Is it so that when someone overclock their system the CPU speed has to be the right one so that their RAM speed can achieve 400MHz for a DDR2 800 RAM?

I heard people overclock their RAM, so if the rules stated the speed can't be over 400MHz for DDR2 800, how can overclock the RAM possible? Is there a reason why the chart shows speed up to 1000 for multiplier 14, 800/7, CPU FSB 250, that will be 500MHz? So this breaks the rule because it's over 400MHz?

_"Let's say we hold one factor constant, the memory setting (put it at DDR2 800). With a CPU multiplier of 10 or below, the divider is 5. A multiplier of 11 or 12 gives a divider of 6. A multiplier of 13 or 14 gives a divider of 7. A multiplier of 15 or 16 gives a divider of 8. See a pattern?"_
This part i ...think i might get it... but how does one get the divider for them? why DDR2 667's divider is 6 on multiplier of 10x? Why DDR2 667 divider is 7 if multiplier is 11, etc..

Sorry for the question, this is what students do :x

please bare with me


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## GuardianOdin

sign me up,looks great


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## durch

Quote:


Originally Posted by *Notorious* 
Great great article, i understand more, but i hope i don't understood wrongly haha.

Ok so what's the main purpose of this information and chart? :x is it so that when overclocking, we can get the desired RAM clock speed? And because usually when people OC their system they forget about the divider and their RAM get underclocked? Is it so that when someone overclock their system the CPU speed has to be the right one so that their RAM speed can achieve 400MHz for a DDR2 800 RAM?

The purpose is to help people better understand how memory speed is calculated. What you do with the information is up to you, but it should help you get a better overclock







My main motivation was that a lot of people still say things like "set the divider" which was an option in the BIOS in the socket 939 and DDR days, but no longer has the same meaning with socket AM2 and DDR2 memory.

Quote:


Originally Posted by *Notorious* 
I heard people overclock their RAM, so if the rules stated the speed can't be over 400MHz for DDR2 800, how can overclock the RAM possible? Is there a reason why the chart shows speed up to 1000 for multiplier 14, 800/7, CPU FSB 250, that will be 500MHz? So this breaks the rule because it's over 400MHz?

Take another look at rule #2, in bold it says "at the stock HTT of 200MHz". The memory's speed cannot exceed 400MHz for DDR2 800 when the HTT is 200MHz, however if you increase the HTT beyond 200MHz you can increase the speed of the memory beyond 400MHz. It can get confusing I know.

Quote:


Originally Posted by *Notorious* 
_"Let's say we hold one factor constant, the memory setting (put it at DDR2 800). With a CPU multiplier of 10 or below, the divider is 5. A multiplier of 11 or 12 gives a divider of 6. A multiplier of 13 or 14 gives a divider of 7. A multiplier of 15 or 16 gives a divider of 8. See a pattern?"_
This part i ...think i might get it... but how does one get the divider for them? why DDR2 667's divider is 6 on multiplier of 10x? Why DDR2 667 divider is 7 if multiplier is 11, etc..

Sorry for the question, this is what students do :x

please bare with me

The divider is determined by following rules 1-3 described in my original post. Remember, these rules are used to calculate the memory's speed when the HTT is 200MHz, I think that's the part you're struggling with.

Taking your example of DDR2 667, consider this. At a CPU multiplier of 10x, and the HTT at 200MHz, the total CPU speed is 2000MHz. A divider of 5 gives 400MHz, which violates rule #2 (memory can't run faster than 333MHz at DDR2 667 and an HTT of 200MHz). A divider of 6 gives 333MHz, all rules are satisfied. I divider of 7 gives 286MHz, rules 1 and 2 are satisfied but rule 3 is violated because a divider of 6 works just as well.

If you increase the CPU multiplier to 11x (and hold the HTT at 200MHz), the total CPU speed increases to 2200MHz. Now a divider of 6 gives 367MHz, rule #2 is now violated. The computer knows this and increases the divider to 7, giving 314MHz, satisfying all rules.

It can be complicated I know, but if you understand the 3 rules you should be able to figure out what the divider will be for any combination of CPU multiplier and memory setting without using the charts. But until then, the charts can be a great quick reference.


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## Notorious

Quote:


Originally Posted by *durch* 
The purpose is to help people better understand how memory speed is calculated. What you do with the information is up to you, but it should help you get a better overclock







My main motivation was that a lot of people still say things like "set the divider" which was an option in the BIOS in the socket 939 and DDR days, but no longer has the same meaning with socket AM2 and DDR2 memory.

Take another look at rule #2, in bold it says "at the stock HTT of 200MHz". The memory's speed cannot exceed 400MHz for DDR2 800 when the HTT is 200MHz, however if you increase the HTT beyond 200MHz you can increase the speed of the memory beyond 400MHz. It can get confusing I know.

The divider is determined by following rules 1-3 described in my original post. Remember, these rules are used to calculate the memory's speed when the HTT is 200MHz, I think that's the part you're struggling with.

Taking your example of DDR2 667, consider this. At a CPU multiplier of 10x, and the HTT at 200MHz, the total CPU speed is 2000MHz. A divider of 5 gives 400MHz, which violates rule #2 (memory can't run faster than 333MHz at DDR2 667 and an HTT of 200MHz). A divider of 6 gives 333MHz, all rules are satisfied. I divider of 7 gives 286MHz, rules 1 and 2 are satisfied but rule 3 is violated because a divider of 6 works just as well.

If you increase the CPU multiplier to 11x (and hold the HTT at 200MHz), the total CPU speed increases to 2200MHz. Now a divider of 6 gives 367MHz, rule #2 is now violated. The computer knows this and increases the divider to 7, giving 314MHz, satisfying all rules.

It can be complicated I know, but if you understand the 3 rules you should be able to figure out what the divider will be for any combination of CPU multiplier and memory setting without using the charts. But until then, the charts can be a great quick reference.

I sense a lot of answers in your reply, but i have to read it more than 1 times haha, ok hmm so basically the divider for 667, 800 etc., are determine by what my CPU Speed are?

Example:
DDR2 800, Multiplier 16x, HTT 200MHz
divider 5 = 640MHz (violation)
divider 6 = 533MHz (violation)
divider 7 = 457MHz (violation)
divider 8 = 400MHz (satisfied)

So that means the divider is 8 for DDR2 800, Multiplier 16x, HTT 200MHz. (right?)

If memory cannot exceed 400MHz at HTT 200MHz for DDR2 800
What MHz the memory cannot exceed IF the HTT is 210 for DDR2 800

If memory cannot exceed 333MHz at HTT 200MHz for DDR2 667
What MHz the memory cannot exceed IF the HTT is 210 for DDR2 667

Thanks a lot! I understand more


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## durch

Quote:


Originally Posted by *Notorious* 
so basically the divider for 667, 800 etc., are determine by what my CPU Speed are?

Not exactly. The variables in determining the divider are a) CPU multiplier and b) memory setting (i.e. DDR2 800, DDR2 667, etc). So for any given memory setting, the only other thing you need to know is the CPU multiplier. Total CPU speed depends on the CPU multiplier AND the HTT, but your divider stays the same no matter what HTT you use. The divider only depends on the memory setting and CPU multiplier.

Quote:


Originally Posted by *Notorious* 
Example:
DDR2 800, Multiplier 16x, HTT 200MHz
divider 5 = 640MHz (violation)
divider 6 = 533MHz (violation)
divider 7 = 457MHz (violation)
divider 8 = 400MHz (satisfied)

So that means the divider is 8 for DDR2 800, Multiplier 16x, HTT 200MHz. (right?)

If memory cannot exceed 400MHz at HTT 200MHz for DDR2 800
What MHz the memory cannot exceed IF the HTT is 210 for DDR2 800

If memory cannot exceed 333MHz at HTT 200MHz for DDR2 667
What MHz the memory cannot exceed IF the HTT is 210 for DDR2 667

Thanks a lot! I understand more

There you go, you're getting it! As the HTT is increased, the divider will stay the same. So the memory will start to overclock as you increase the HTT.

You can think of it like this:
Memory is rated to run at certain speeds, timings, and voltages at a stock HTT of 200MHz. For DDR2 800, that speed is 400MHz. The manufacturers make no guarantee that the memory will work at faster speeds, so the computer is setup to choose a divider that won't allow the speed to exceed 400MHz in a traditional non-overclocked system with the HTT equal to 200MHz. That's why when figuring out the divider you assume the HTT is 200MHz. But once the divider is chosen, it stays the same unless you change the memory setting or CPU multiplier. So as the HTT increases, so does the memory's speed. You can take it well beyond 400MHz if you have good memory.


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## Notorious

Cool! So how much will the memory get increase if i increase HTT to 210, if HTT 200 results in 400MHz for memory?

How much can we push the memory? I'm using Corsair TWIN2X2048x6400 kit, how far to increase that the result will be safe and sweet.

By the way, since i don't know how to overclock the professional way, i only know how to do it by adjusting the multiplier like everyone said especially Tom's Hardware, so i wanna learn to use the multiplier and HTT to overclock so that i can overclock the memory as well.

I can't increase the HTT somehow, i've tried few times, there was one time only a mere 210 and leaving the multiplier on it's default 13x, the PC won't boot up, did i miss something? I noticed cool and quiet is disabled, what else should i check for?

Thanks durch


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## durch

Ok, so the first thing you do is figure out what divider you're using based on the two factors a) CPU multiplier and b) memory setting. Once you know the divider (and know that the divider won't change unless you change the memory setting or CPU multiplier), then you can calculate the memory's speed using the equation in my original post:

memory speed = (total CPU speed)/divider

So as the HTT is increased to overclock the CPU, the memory will also start to overclock.

You asked how far you can push your memory, and that's something you can only find out through experimentation. If the memory becomes unstable, the first thing you should do is loosen the timings from 4-4-4-12 to 5-5-5-15. You'll probably need to do this somewhere between 425MHz (850 effective) and 475MHz (950 effective), but that's just an estimate, no way to know for sure where your RAM will become unstable. If you hit instability with 5-5-5-15 timings, then consider giving your memory a bump in voltage, nothing more than 0.1 volts though to be safe. After that, your options are pretty limited.

I'm working on an overclocking guide for AM2/DDR2 systems, I'll let you know when I've completed it. But until then, there's some overclocking guides here for socket 939 systems that might be of some help (although they use DDR memory so many of the steps aren't relevant to DDR2 and socket AM2). Check out the stickies in the AMD General section. You can also browse google for some good guides. Goodluck!


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## Notorious

Oh thanks, i think that guide will help me understand more, but you've did a good job so far, i think i finally understand, i just need to get my hands dirty and experience it.

So far i did some simple test

I tried Multiplier 13x (default) and HTT 200MHz (default) = 2600MHz
Divider for DDR2 800 is 7 (371) so divider will stay the same (7) heh

So now i increase the HTT to 230MHz, 13x230=2990MHz
2990/7=427MHz

I used CPU-Z and checked the memory and got 427.3MHz

This....means.....i'm successful eh?

The hard part is to overclock to the CPU speed i want sometimes i can't get the RAM speed i want, it maybe too much or too little.

To use multiplier 12x for example, to get the desired speed of 3000MHz, i increase HTT to 250MHz and since divider is 6, the results is 500MHz, that's a bit too much for me i think :x

I guess multiplier 10 and 12 are got memories above DDR2 800, so far i find 13x has some sweet spots, like 13x240MHz = RAM 445MHz, 13x250MHz = RAM 465MHz.

But i think i will try 13x240, since my MOBO won't allow me to increase CPU voltage over 1.350V so i can't go above 3100MHz i think.

Thanks. Lookin forward to the AM2/DDR2 guide from you.


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## adramalech707

okay i am having such a delema trying to figure out an over clock...i have been racking my brain over how to write an equation of the two different things...the memory divide that cannot exceed a max speed and the correct divide value dependent on the divide and dependent on the cpu multiple...whooowwww i hope i didn't try and confuse anybody...

okay i have a x2 4600+ @200x12(2400mhz) 1.35volts....

i also have 4gb 2x twin2x2048-6400c4...which is proving very difficult to overclock my cpu with 4 stick population!!!!







:swearing:

on a ga-m59sli-s5 (which has problems going above 312mhz fsb!!!







)

i have tried numerous different approaches to ocing this chip on this board in order to not get the newer meaning of 1:1 ratio which i have found to me is unreachable!!!!

i am know trying to get 3.2ghz just because i think it would be cool and because my motherboard i think can handle the overclock...but the memory is as i stated earlier a pain in the arsseee to keep undercontrol and stable in an overclock...

the reason why i am trying for 3.2ghz is because at the time i was thinking to keep memory under 800mhz (or 400) but i forgot that to divide by 8 i would have to lower divide to 533 which would only allow for 267mhz and then i would have to rethink the whole idea...

can someone please enlighten me on an easier approach than what i am trying







because i cannot seem to keep the speed of the processor under the limit of the memory...if i am wrong please tell me so i don't go around thinking the impossible with this oc


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## slowpoke2006

OK i have just one question If you have DDR2 667 and you now it will run over 800 can you just set it to DDR2 800 in the bios? so far i know it runs stable at 800 just haven't tried to go any higher yet. Edit ok i passed the 900 mark on my mem. running 5-5-5-15-20 2T at 2.0v. and i can keep going but i have just one problem I guess i ended up with a bad board b/c my HTT clock wont go over 280 don't know why, but in Ntune i got it to go all the way up to 340. Ive tried to drop the HT Multy down to 4 but steal no good. So i sad what the heck now I'm running at DDR2 800 speeds with a Htt set at 200.9 so now i can push my ram even farther maybe even get to 1000 at 2.1v who knows it seams to be a really good batch of memory. My HT will run stable at 1400mhz after that it down for the count.


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## karossii

I want a cookie







- my MSI K9A2 CF mobo has a CPU:memory ratio option in the BIOS (AMI BIOS A7388AMS rev 1.6).

It is AM2 and uses DDR2.

Which is why this and other posts have been confusing me with all the talk about dividers with options I can't seem to access. Where do I learn more about overclocking with this seemingly archaic usage?


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## durch

Quote:


Originally Posted by *slowpoke2006* 
OK i have just one question If you have DDR2 667 and you now it will run over 800 can you just set it to DDR2 800 in the bios? so far i know it runs stable at 800 just haven't tried to go any higher yet. Edit ok i passed the 900 mark on my mem. running 5-5-5-15-20 2T at 2.0v. and i can keep going but i have just one problem I guess i ended up with a bad board b/c my HTT clock wont go over 280 don't know why, but in Ntune i got it to go all the way up to 340. Ive tried to drop the HT Multy down to 4 but steal no good. So i sad what the heck now I'm running at DDR2 800 speeds with a Htt set at 200.9 so now i can push my ram even farther maybe even get to 1000 at 2.1v who knows it seams to be a really good batch of memory. My HT will run stable at 1400mhz after that it down for the count.

You know this is a question I've had for awhile too but never bought DDR2 667 to experiment with. It sounds like you were able to set the DDR2 667 to DDR2 800 in the BIOS without overclocking the reference clock (HTT), is this correct? I'm definitely interested in knowing.

As for your reference clock (HTT) not going over 280, try giving the motherboard voltage a few bumps. Also, make sure it's not your CPU that's holding you back. When testing for the max reference clock (HTT) you want to make sure neither the CPU or memory goes over stock speeds.

Quote:


Originally Posted by *karossii* 
I want a cookie







- my MSI K9A2 CF mobo has a CPU:memory ratio option in the BIOS (AMI BIOS A7388AMS rev 1.6).

It is AM2 and uses DDR2.

Which is why this and other posts have been confusing me with all the talk about dividers with options I can't seem to access. Where do I learn more about overclocking with this seemingly archaic usage?

<-- starts baking

But you cheated, you're using a 790 board that came out after I wrote this lol. I haven't used an AMD system in several months now, interesting to see that at least some boards are going back to the 939 days of ratio's. Because the divider depends on both that ratio and the CPU multiplier, the ratio you choose will only be correct if you're running an even CPU multiplier. It's going to make it a little hard to figure out what your memory speed actually is, but that's what CPU-Z is for. I'm not sure what ratios your board gives, but here's some general correlations for an even CPU multiplier and a stock (200MHz) reference clock:

1:1 DDR2 400
3:4 DDR2 533
3:5 DDR2 667
1:2 DDR2 800
2:5 DDR2 1000
3:8 DDR2 1066


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## Lightning_Scythe

a friend of mine is running an X2 6000+ @ stock with 2 2GB DDR 2 800mhz sticks of ram.

based on ur article i wud believe that the divider would b 8, and thus have a memory speed of 3000/8 = 375 mhz per channel or 750 mhz. this is confirmed by the ddr2 ram divider charts which u linked us to.

however his frequency monitor (i believe he is using ntune) is saying that his frequeny is 804 mhz. what would cause this, considering he has done no overclocking?

he is using an asus m2n32-sli vista edition


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## prracer6

Im new to PC OCing and this is a lot of info, but really good.


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## Bouncer

I read this about 4 times finally got it. It's very simple. Nice job.


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## Slink

Yes, excellent intro info. Thanks! I used your AMD OC guide to get me started, now I have a 12.5% stable CPU boost.

However, I have a burning question. See, my mobo supports up to DDR2-800 speed. If I buy a higher speed RAM (such as 1066) with the same timings as my current ram (current= 800 5-5-5-15) shouldn't it be easier to achieve tighter timings with the faster ram set to 800 speed? I ask so that I can further my understanding of RAM timings in relation to "speeds". I already know that as speed goes up, timings generally get looser.

Thanks! Please link if you know a good one. There is so much to sift thru here!!


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## pioneerisloud

Honestly, AMD CPU's prefer tighter timings vs. Higher speeds. DDR800 @ 4-4-4-12 for example would generally yield higher performance than 1066 @ 5-5-5-15. But honestly you won't see any real world performance difference between the two.

And yes, DDR1066 would likely get tighter timings @ 800MHz. But you can also just get some DDR800 that will run with tighter timings anyway. So its really up to you.


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## Slink

Quote:


Originally Posted by *pioneerisloud* 
Honestly, AMD CPU's prefer tighter timings vs. Higher speeds. DDR800 @ 4-4-4-12 for example would generally yield higher performance than 1066 @ 5-5-5-15. But honestly you won't see any real world performance difference between the two.

And yes, DDR1066 would likely get tighter timings @ 800MHz. But you can also just get some DDR800 that will run with tighter timings anyway. So its really up to you.

Thanks! I didn't know about the specifics in regard to AMD chips.

In the light of your answer to my question, I would say that if I can find some higher-speed RAM with extra tight timings, and without an insane voltage requirement, that would be the cream of the crop, right?!


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## durch

Quote:


Originally Posted by *Slink* 
Thanks! I didn't know about the specifics in regard to AMD chips.

In the light of your answer to my question, I would say that if I can find some higher-speed RAM with extra tight timings, and without an insane voltage requirement, that would be the cream of the crop, right?!









Ideally yes, but you're going to have a hard time finding memory over DDR2 950 speeds that has anything tighter than 5-5-5-15-2T. Like Pioneerisloud pointed out, buying DDR2 1066 RAM with 5-5-5-15-2T timings and underclocking it to DDR2 800 with 4-4-4-12-2T timings won't be any different than just buying DDR2 800 memory rated for 4-4-4-12-2T timings. 1066 is almost always more expensive than 800 memory, so your best bet is probably to just get a 4-4-4-12 set of DDR2 800.

CPU speed is far more important than RAM speed. Spending a lot of money on a set of RAM isn't a good idea IMO because the difference between running say DDR2 900 4-4-4-12-2T (really good for AMD) or DDR2 900 5-5-5-15-2T isn't really noticeable, but the price difference could be enormous. You'd be better off saving the money or spending it on a better CPU.

As for the statement about low voltage RAM being better, that's not necessarily true. With a CPU, a lower Vid means the CPU will usually overclock better than a CPU with a higher Vid because both CPU's have the same "max voltage" that can be safely applied, so the CPU with the lower Vid has more headroom. The same is NOT true with RAM, and the reason for this is different RAM uses different ICs (internal controllers). The IC of the memory determines the voltage needed and the overclocking capability of the module. A lot of the memory with lower voltage needs use ICs that frankly do not scale well with voltage. So even though one memory stick with a certain IC can run 2.2v no problem does not mean that a different memory stick with a different IC rated for say 1.9v can safely run 2.2v, or that increasing the voltage to 2.2v will give any improvement in stability.


----------



## Slink

Okay, I don't wanna come off as weird, but I pretty much love you. Hahaha. (You have been incredibly helpful in multiple instances, and I am thankful.)

Thank you so much for the heads-up. I have to say, I could keep cranking my CPU a bit, but the RAM gives out, unless I loosen the timings. I had everything running pretty hot for a few min to test limits, and with RAM running at tighter timings, I saw a pretty intense boost in speed (but the system was STILL unstable).

Whatever the case, my CPU is still weak, and I plan on upgrading. The RAM that I have is definitely a bottleneck, but as CPU speed goes up, RAM does so proportionately (until you need to loosen timings) right? -Thanks!


----------



## Quantum Reality

Thanks for the tutorial and info. This answered some odd CPU-Z data I saw.







(see attachment)

However I am wondering why memtest86+ thinks my DDR2-667 @ 600 is 685? Is memtest not reading the divider/memory speed/whatever-it-is properly? If it helps I have am Asus M3A whose BIOS has "Limit" and "Manual" settings. I have it at Limit DDR2-800 presently, but the board is obviously still choosing to go by the SPD. It is Kingston 4-4-4-12 DDR2-667 and I've heard reports it can be safely taken up to 800. So I guess I could just solve my problem completely by fixing it at 800 and calling it a day.









But some analysis of this anomaly would be helpful.


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## durch

Hmm, what CPU are you running with the DDR2 667 memory? I'm not sure if Phenoms follow these same rules, but there is absolutely no way to set the speed of the memory independently of the CPU speed for X2's. They MUST follow the rules in this guide. I'd trust CPU-Z over Memtest, but you should be able to verify the speed on your own doing the math.


----------



## Quantum Reality

Quote:


Originally Posted by *durch* 
hmm, what cpu are you running with the ddr2 667 memory?

A64 x2 4600+.







(2.4 GHz stock speed + AMD heatsink/fan)


----------



## durch

Quote:


Originally Posted by *Quantum Reality* 
A64 x2 4600+.







(2.4 GHz stock speed + AMD heatsink/fan)

Ok, so you're running the X2 4600+ at stock 2.4GHz speed. So your CPU multiplier is 12 and your reference clock is set to 200MHz (200 x 12 = 2400MHz). If you look at the memory divider charts you'll see that 300MHz (DDR2 600) is completely normal for a reference clock of 200MHz, a CPU multiplier of 12, and a memory setting of DDR2 667.

If you do not plan to overclock, I would recommend the following change to re-establish speeds close to what your memory and CPU are advertised to run.

CPU Multiplier: 11x
Reference Clock: 218MHz
Memory Setting: DDR2 667

This will run your CPU at 2398MHz, or roughly the stock 2.4GHz. Lowering the CPU multiplier while holding the memory setting constant drops the CPU-->Memory divider from 8 to 7. So 2398/7 = 342.5MHz, or DDR2 685 speeds, just slightly overclocked from the rated 667 speeds. You should be able to run such a mild overclock without anymore voltage or looser timings. However, is your memory rated for 1T at 667 speeds? You might not be able to keep that tight timing at 685, but if it's decent memory you might be able to.

Also, one last thing to point out is that your HT Link will be running at 218 x 5 = 1090MHz, a 90MHz overclock from the default 1000MHz HT Link speed. Most boards can go up to 1400MHz and higher without breaking a sweat, others freak out at even a slight increase. So if you hit instability, try lowering the HT multiplier to 4x.


----------



## Quantum Reality

Excellent! Thank you. I'll be doing this shortly and reporting back to see how things improve. If anything my folding will speed up.









Oh, is prime95 a valid test for instability due to increased HT speeds?


----------



## durch

Quote:


Originally Posted by *Quantum Reality* 
Excellent! Thank you. I'll be doing this shortly and reporting back to see how things improve. If anything my folding will speed up.









Oh, is prime95 a valid test for instability due to increased HT speeds?

Yes, that and Orthos. By the way are you going to overclock your CPU at all? CPU speed is always more important than memory speed, as long as the memory isn't a complete bottleneck.


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## Quantum Reality

Hmm. Well, I don't know how far I could take the CPU on a stock cooler. What's a good overclock that would pull my memory up to 667 speeds just via the divider? (I'm actually more of an overclocker on the Intel side, heh - see sig rig.







)

Edit to add -

Looking at the divider table for a 12x multiplier I see I could prolly get away with a 225 MHz-ish speed and get up to 667-ish. Nice! I'll give it a shot instead of messing with this juggle the ref clock and multiplier business.









Edit * 2 - YOUCH! I just punched in 220 MHz on the "FSB" without calculating what the output speed was before rebooting. 2.64 GHz! On a stock cooler, too. Well, nothing for it. I'm Prime95ing as we speak and if it holds up on a blended test for a couple of hours I'll call 'er good.


----------



## durch

Quote:


Originally Posted by *Quantum Reality* 
Hmm. Well, I don't know how far I could take the CPU on a stock cooler. What's a good overclock that would pull my memory up to 667 speeds just via the divider? (I'm actually more of an overclocker on the Intel side, heh - see sig rig.







)

Unfortunately the older Windsor cores aren't great overclockers. My X2 4200+ only hit 2.73GHz with a Zalman 9700 and 1.47v and that was very typical. If yours is a Windsor core of the same generation you're probably looking at similar results and might only be able to hit around 2.5-2.6GHz on stock volts and stock cooler. I also owned an X2 4000+ Brisbane that hit 2.6GHz stock volts and 2.8GHz on 1.45v.

There's so many combinations of reference clock, CPU multiplier, and memory setting to give you different memory speeds and HT Link speeds at the same CPU speed. Why don't you see how far you can take your CPU on stock volts and report back. Try these settings and this procedure:

CPU multiplier 12x
memory setting DDR2 533
timings: 4-4-4-12-24-2T (or 5-5-5-15-26-2T to play it safe)
HT multiplier 4x
manually lock PCIe frequency at 100MHz
turn off cool'n'quiet
manually set the CPU voltage to 1.30-1.35v (whatever gives you temps below 60*C at load, if your 4600+ is a Brisbane and not a Windsor the temp reading will be worthless and completely off)
manually set the memory voltage to whatever they need

Now start increasing the reference clock by 2-3MHz at a time. Try to take it from 200MHz up to around 215-220MHz slowly, as I think that's where your CPU will top out. After each 2-3MHz increase, run Orthos or Prime95 for a couple minutes to make sure it's somewhat stable. If you pass, try another 2-3MHz bump. Let us know how high you can take it on stock volts, and keep an eye on temps, increased frequency is linearly related to the change in temperature, so temps will go up a bit, just no where near as much as a voltage increase causes (which is quadratically related).

EDIT: Once I know the CPU speed you'll be running at, I can give you some combinations of settings to get your memory as close to DDR2 667 as we can without stressing the HT Link too much. Also, were you able to run DDR2 685 with 1T?


----------



## Quantum Reality

Oh, the 214 MHz + 11x trick? Worked great. I was still at 1T by CPU-Z. Don't have a screenie to show you, though.

As you can see I basically just leaped straight into the big leagues on the (and yeah, it's a Windsor core) 4600+. As noted I'm P95ing with a blended test and leaving CPU-Z and HWMonitor running to check voltages and temps. I cheated and opened the window letting in near-zero-degree C air in which I think is keeping my temps down at around 38/38 on both cores.









Edit - as this is getting a bit off topic, could a moderator split some of the posts into a separate thread just for discussing my 4600+ overclock? Apologies for the drift....


----------



## Slink

Quote:


Originally Posted by *Quantum Reality* 
Edit - as this is getting a bit off topic, could a moderator split some of the posts into a separate thread just for discussing my 4600+ overclock? Apologies for the drift....

First and foremost, I agree. Sorry for the off-topic post slew.

Quote:


Originally Posted by *Quantum Reality* 
Oh, the 214 MHz + 11x trick? Worked great. I was still at 1T by CPU-Z.

I have the same exact core, AFAIK. Is yours 90nm or 65nm mfctr process? I was considering doing this, but I think ended up with faster performance at 12x, with looser RAM timings.

Quote:


Originally Posted by *durch* 
Unfortunately the older Windsor cores aren't great overclockers. My X2 4200+ only hit 2.73GHz with a Zalman 9700 and 1.47v and that was very typical.

I attest to this, attempting to whine about how I can only get about 2.7GHz out of mine. I'm sure the 65nm process model could squeeze much more performance out than my E-Z Bake Oven 90nm model. (I could have gotten a grill-shaped heatsink and cooked some steaks.) Sitting pretty cool (39*C:46*C) at 2.7GHz @ 1.4vCore with a Gigabyte 3D Rocket cooler.

Quote:


Originally Posted by *Quantum Reality* 
I cheated and opened the window letting in near-zero-degree C air in which I think is keeping my temps down at around 38/38 on both cores.









Hahaha I did that too, recently. I had to leave the house, but I wanted to do a safe stability test, so I set my PC on the floor, opened the bottom and top of my "storm" window, and blocked the airspace under my door with a pillow (and also the cold air return). It was about 25*F outside.


----------



## COBSAD

Nice man, thank you and you rock.


----------



## Notorious

I'm back after so long; to embark on the next black edition journey hehe, i've learned a lot here but i didn't actually have that much success with HTT, maybe due to the MOBO, so the end result is a simple 200x16=3200 with Vcore to 1.400. It was fun.

I'll probably be gettin the next Black Edition which is the Phenom II X3 720 BE, and again will surely overclock it, but i wonder if this guide will still be relevant? And with DDR2 1066? All rules the same?,

After reading a few thread, there's mentioned that the multiplier has to be a round number like 18 instead of 18.5, somethin about how the memory controller works, so i don't understand this, i know that dividers has to be a round number also, but multiplier..i'm not really sure, is this the fact?


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## durch

I have not worked with any Phenoms, nor have I read a lot about how they're overclocked. I do know that they have a faster HT Link and can actually be set to DDR2 1066, which means there's at the very least new divider instructions, if not a completely different system. Hopefully some more guides and information will start to be posted for Phenoms, especially with AM3 out now. I'd be happy to write something up if someone would donate me an AM3 CPU and board







haha.


----------



## Notorious

Hmm I see, and since the CPU is an AM3 socket, it will also work with a AM2+ board with support up to DDR2-1066, and above that for AM3 board which usually supports DDR3, I heard some even support both DDR2 and DDR3.

Not really sure if I would go for AM3 and DDR3 yet, but sounds like somethin i have to dive in for future proof reasons. And then comes DDR3-1333, 1600, more headache I guess haha. So mainly I would stick to AM2+ board and DDR2 still, depends on the price of AM3 board and DDR3 tough.

There's a X3 720 BE club here, looks like the overclock is the same as the previous Black Edition, just adjust the multiplier heh, you can see some examples on their overclocking results.

http://www.overclock.net/amd-cpus/47...x3-720-oc.html

As you can see some use half multiplier numbrs like 18.5, 16.5, hmm seems to work fine heh.


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## Dudeson169

thank you for this guide, helped me alot to see why my ram was being underclock3d


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## durch

I hate how rep is anonymous, to the person who left this message:

Quote:

Good guide. But HTT is Intel's Hyper Threading you want HT. *Look it up?* Good work I did not know all this.
No I don't want HT, I want reference clock. HTT is indeed Intel's hyper threading and is an incorrect term for AMD's reference clock. However, AMD never established a name for the reference clock, and because of that motherboards call that value all sorts of things that are incorrect like CPU Frequency and HTT. Many people confuse the reference clock with the HT Link, and at the time of writing the original post, HTT was by far the most widely used term on OCN to refer to the reference clock and HT was used for the HT Link. Many people used HTT to refer to BOTH the reference clock and the HT Link. Needless to say there was always confusion when people tried helping with overclocks. In fact I hadn't seen a single post where anyone called it the reference clock. Since the point of this post was to help people, I originally used HTT not reference clock so OCN users would understand what I was talking about.

It wasn't until I wrote my overclocking guide that I attempted to get people to use reference clock and HT Link to help clear up future confusion. I saw the term reference clock used on another web site and the term made the most sense to me, as the CPU frequency and HT Link reference it to calculate their speed. I decided to use this more proper term in my AMD Socket AM2 Overclocking Guide that I wrote 6 months after writing this guide. Since my overclocking guide references this thread, I switched HTT to reference clock in the original post and added an edit that explains that the first few responses will use HTT to refer to the reference clock. I did not edit the early responses that use HTT because the posters asking the questions used HTT and I wanted my answers to their questions to match up to avoid confusion.

And there was no need for the sarcastic "look it up?"








I'm well aware







But thank you for the rep







I dunno why people called it HTT, they were calling it that well before I joined. HyperTransport Technology maybe? Similar to the "technology" of HyperThreading Technology? I dunno, you'd have to ask them.

From my overclocking guide:

Quote:

Reference Clock
This is the setting that starts at 200 and is increased to overclock your computer. This is the single most important setting, as the CPU, HT Link and memory all reference this number when calculating their speed. The reference clock is often incorrectly referred to as the FSB, which is an Intel term that has no bearing on AMD 64 X2 systems. The reference clock is also referred to as the HT, HTT, CPU speed, and many other terms that arenâ€™t really correct, however many people and motherboards use them. It is important to note that unlike Intelâ€™s FSB, no data is actually transferred on the reference clock. It is merely a number created by the clock generator that other devices reference to calculate their speed. Your motherboard should give you the option to increase the reference clock by any whole number, up to a certain max value such as 400 (i.e. Auto, 200, 201, 202, 203, â€¦, 398, 399, 400). It is usually a bad idea to increase the reference clock by any more than 10MHz at a time, as large changes can cause your system to fail to post.


----------



## Slink

Yet again, a wealth of information--much of which I was unaware. Thx!


----------



## Sandman8709

Ehh this kinda makes since but it hurts my head.


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## durch

Quote:


Originally Posted by *Sandman8709* 
Ehh this kinda makes since but it hurts my head.

Haha, well if you provide the specifics of your system and your goals I can help you work out the possible RAM and CPU speeds.

What's important is:
1) the max CPU multiplier available to you
2) the highest *stable* CPU clock you've achieved with reasonable load temps (load temps below 60*C, stable meaning it passes several hours of an Orthos small FFT test and several hours of an Orthos blend test)
3) The speed, timings and voltage of your RAM (i.e. DDR2 800 rated for 4-4-4-12 timings at 2.1v)
4) Any info on RAM testing you've done, if you've done any

Get back to us with that and we can help you get the most out of your memory.

EDIT: I'll be away from a computer for 3 days starting tomorrow.


----------



## Slink

Durch is among the most helpful, if not the best help with overclocking DDR2 RAM on an AMD motherboard, but there are many others here who can help you as well (including me). I learned (mostly from Durch) how to OC DDR2 on AMD boards.

It always helps if you have a digital camera to take pictures of your BIOS/CMOS setup screens!









Good luck, and have fun! (GLHF)







Let us know if you need help.


----------



## goodolsen

I just found this thread and I'm hoping its still monitored. I'm looking for some help getting the best out of my system.

I'm running an X2 4800+ (stock settings 200 x 12.5 for 2.5GHz) Right now I've got it set to 240x 12.5 running at 3.0GHz. It's showing my RAM is running at 428.3. I'm using Transcend DDR2-800 w/5-5-5-18-2T timings.

This is the link to my CPU-Z validation. http://valid.canardpc.com/show_oc.php?id=583368

My question is this, have I done a good job OC'ing my machine, or are there things I can do better to get the most out of my CPU and RAM? Would changing the multiplier to 12 and the Bus to 250 be better? Should I try changing the timings on my RAM?

Any feedback is appreciated.

-goodolsen


----------



## durch

Hey goodolsen,

Looks to me like a pretty good overclock. The older X2 4800+ probably won't go much past 3.0GHz (your current clock) if at all, but CPU speed is far more important than memory speed so if you want more performance, trying to push your CPU further is the place to start. If that's the highest stable CPU speed you can reach, then the only other thing to try is to lower your CPU--> Memory divider to increase your RAM speed, or to tighten timings at your current speed.

AMD AM2 systems don't see much benefit from RAM speeds over 800MHz, they are usually a little more responsive to changes in RAM timings. So my recommendation is to try tightening your timings a bit. But if they're rated for 5-5-5-18 at 800MHz and you're currently at 857MHz, I doubt you'll get to 4-4-4-15, but you might be able to tighten a few a little.

You can lower your CPU --> Memory divider (currently at 7) to 6 by changing your CPU multiplier to 12x instead of 12.5x. Increase your reference clock from it's current 240MHz to 250MHz to re-establish the 3.0GHz CPU speed. At this same CPU speed but new divider of 6, you'll be running your RAM at 1000MHz up from 857MHz. A big jump, so your RAM might not be able to handle it. But if it can, it should give you a small boost in performance.

Good luck, let us know how it goes.


----------



## goodolsen

Well after some playing around with settings, I actually lowered the CPU speed from 3.0 to 2.8GHz so that its more synch'ed with the RAM. Since I don't have high quality RAM, I didn't want to push it too far.

Also the CPU was running about 115-125 F, and with it being a Texas summer in triple digits I figured lowering the speed wouldn't be a bad idea.


----------



## durch

Quote:


Originally Posted by *goodolsen* 
Well after some playing around with settings, I actually lowered the CPU speed from 3.0 to 2.8GHz so that its more synch'ed with the RAM. Since I don't have high quality RAM, I didn't want to push it too far.

Also the CPU was running about 115-125 F, and with it being a Texas summer in triple digits I figured lowering the speed wouldn't be a bad idea.

Synced with the RAM? Lowering CPU speed = loss in performance, always. I'm not sure what you mean by synced with the RAM but whatever you think is going on, it's bologna lol. Kick it back up to 3.0GHz if you want the most out of your system. CPU speed is far more important than RAM speed so long as your RAM is running over 400MHz (DDR2 800 speeds). CPU speed usually more important than RAM speeds even if your RAM is running under 400MHz. Never take a hit in CPU speed for more RAM speed. And 125*F is only 51*C. My X2 4200+ use to run at 58*C during load with the stock cooler and worked flawlessly. X2 Windsors (what you have) can take up to 60*C for 24/7 use safely, your temps are fine if 125*F is as hot as it gets.


----------



## goodolsen

Yeah, I didn't think it made a lot of sense, but after a long weekend and not much sleep it sounded good. LOL I'll bump it back up tonight, I'm also looking into getting some new RAM. How would the Crucial Ballistix Tracer 2GB with 4-4-4-12-2t timings help? I'm looking at getting 2 sticks, since 2 separate 2GB are cheaper than a 2x2GB pack...go figure.

http://www.newegg.com/Product/Produc...82E16820148215


----------



## durch

Quote:


Originally Posted by *goodolsen* 
Yeah, I didn't think it made a lot of sense, but after a long weekend and not much sleep it sounded good. LOL I'll bump it back up tonight, I'm also looking into getting some new RAM. How would the Crucial Ballistix Tracer 2GB with 4-4-4-12-2t timings help? I'm looking at getting 2 sticks, since 2 separate 2GB are cheaper than a 2x2GB pack...go figure.

http://www.newegg.com/Product/Produc...82E16820148215

There's nothing special about the 2GB Ballistix modules. It was their 1GB modules (2x1GB sets) that had Micron D9GMH IC's and overclocked to around 1100-1200MHz on average for a VERY reasonable price. They were extremely popular on this site about 1.5-2 years ago. I wouldn't dish out $58 for 4GB of Ballistix Tracers when these OCZ Blade's are just as good for $37 shipped after a $10 MIR. Again, older AMD X2's don't see enough benefit from higher RAM clocks to justify buying expensive RAM or 1066 sets. Plus, those OCZ Blades will likely overclock to 1066 speeds if you loosen the timings to 5-5-5-18. But the performance loss from the higher timings often eliminates (or at least makes negligible) any performance gained from the higher RAM speed. AMD X2's just aren't very sensitive to RAM speeds over 400MHz (800 effective). But whats wrong with your current RAM?

EDIT: If you're looking for more performance out of your system, the memory is the least of your concerns. If you game, you'll see the most benefit from a new video card. Here's some options:

$35 - ASUS 9600GSO (after $20 MIR, FREE shipping, comes with CoD 5!)
$80 - Sapphire HD4830 (FREE shipping, very happy with mine)

If you're not gaming then the 8400 is fine, and you'll want to invest in a CPU/board upgrade. If you do game, start with the GPU, that will give you the biggest improvement, and if you can afford more upgrades go to the CPU/board. Your RAM is fine, not amazing RAM but 4GB is 4GB, speed isn't that important for RAM as long as it's DDR2 800 or better. Here's some CPU/board combos:

$210 - AMD Phenom II X4 940BE with Biostar 790GX board (after $80 instant combo savings)
$195 - AMD X3 720BE with ASUS 790GX (after $54 instant combo savings)

The deal on the X3 720BE is good, the deal on the Phenom II X4 940BE is amazing!!! If you have the money, jump on that deal, you'll see huge improvements in overclocking potential and it will be a good amount faster clock for clock (meaning a PhII at 3.0GHz will run faster than your X2 at 3.0GHz). Plus, it's a quad core versus your dual core. It would be an amazing upgrade for your system.


----------



## goodolsen

Nothing wrong with the current RAM, but ive got 5 80mm case fans with red LED's and thought some flashing red LED RAM would look good with it. It would be more for aesthetics than problem resolution. Although my comp is over a year old and it was my first build, so I didn't know nearly as much then as I do now, and I'm learning more every day.


----------



## durch

Yea, an AMD X2 4200+ was my first build too about 3 years ago. Good systems to start on I think, fairly easy to overclock (though they don't go very high haha).

If you want some more performance for games, I'd at least get the 9600GSO (see edit to previous post). It's a good midrange card that will play most games on medium settings, some on high, and for $35 it's so cheap to upgrade. And of course a new PhII and 790GX board will give you all around better performance in everything. But again, for games, always upgrade the video card before you consider upgrading the CPU/board.


----------



## goodolsen

The 8400GS was my upgraded video card, just a few weeks ago. I wanted something a little faster than onboard, and since I don't really game it worked out well. But now that I'm folding a GPU that does well on that might be my next option. The 8400GS doesn't do so well on folding.


----------



## durch

Just shot you a PM but basically the 9600GSO is THE card for folders. It's the card people most often purchase for a folding rig as it's inexpensive but still folds well. And $35 is incredibly cheap for a 9600GSO.


----------



## goodolsen

Alright, so I bumped the CPU back up to 3.01GHz and the RAM is running at 860. So far so good. Still working on getting approval from the 'boss' for the 9600GSO.


----------



## adoit90

Quote:


Originally Posted by *durch* 
Hello all,
EDIT: I changed "HTT" to the more correct term "reference clock". Please note that many of the responses use the term "HTT" and they are referring to the reference clock.

What's the difference between HTT and reference clock?


----------



## HighOC

Thanks !


----------



## MIGhunter

wow, this thread totally through me for a loop.

I have the system in my sig.

My memory is listed as 4-4-4-12 2.2v.

I can change the Multiplier in my CPU since it's the BE version. I was planning on taking my CPU up to either 3.0 or 3.2. Preferably 3.2. I'd go 3.4 but I don't want to mess with voltages etc. Anyway, how can I figure out how to set my memory based on the Multiplier and the Reference Clock? I guess I'm just confused about the whole memory thing. Especially since I can adjust my multiplier.


----------



## Slink

@MIGhunter: prepare to dissipate disgusting amounts of heat. Good luck.







You'll need it. (I have the Kuma as well).


----------



## xquisit

Good read, and thanks +rep

So how does it work for a 965 + 1600mhz ram (advertised at 7-8-7-24) @ 1.6v


----------



## calebchosen

nice post, congrats.


----------



## Cedert

Guys,

I know this thread has been inactive since 14-02-2008, although a google search on AMD overclocking brought me to this thread.

I was wondering if the table and the rules for DDR2 apply to DDR3 as well. For the fact that AM3 together with DDR3 uses higher CPU-Multipliers and higher Mem-Speeds, I've made an expansion on the table that includes multipliers up-to 18 and speeds up-to DDR3-1800Mhz.

Could one of you please confirm (or reject) the attached table? I would be very thankfull.

Greets,

Ceder

(AMD Overclock-Trainee)


----------



## Rik

well, i have a problem , i have the sli platinum and ddr2 1066 ram but i can get it to run at 1066. It just stays at 800 , so how do i fix this? i have an am2+ cpu so it should work, but alas ,, it does not >.<


----------



## durch

Quote:


Originally Posted by *Rik* 
well, i have a problem , i have the sli platinum and ddr2 1066 ram but i can get it to run at 1066. It just stays at 800 , so how do i fix this? i have an am2+ cpu so it should work, but alas ,, it does not >.<

Hey Rik,

Welcome to the forums! Your motherboard and AM2+ CPU should definitely support DDR2 1066. You have to go into the BIOS and find the memory setting option. Once in the BIOS, there is usually an option for controlling the memory that needs to be switched from Auto to Manual. This opens up a lot of new memory overclocking options (like changing the timings and the memory setting). Have you found the memory setting option? There should be an option for DDR2 400, 533, 667, 800, and 1066. It might list it as a ratio instead of a speed. For DDR2 1066, you want a ratio of 1:2.66. Let us know if this helps or if you're still having trouble.


----------



## Rik

still haveing trouble ill post a vid i made showing what happens when i set the ratio to 1.2.66 , i just cant seem to get it to work >.< your help and advice is greatly appreciated so if your can please check out my vids


----------



## durch

Quote:


Originally Posted by *Rik* 
still haveing trouble ill post a vid i made showing what happens when i set the ratio to 1.2.66 , i just cant seem to get it to work >.< your help and advice is greatly appreciated so if your can please check out my vids

Ah ok, that video was very helpful. So you found the option to switch it to DDR2 1066 (which your board did do), your computer just isn't stable at that setting so it can't even launch Windows.

You probably have 1 of 2 problems (or maybe both problems).

1) Your timings are set too tight for DDR2 1066. At DDR2 800 speeds, your timings were probably something like 4-4-4-12, or 4-4-4-15. If they're left on Auto while the memory setting is manually changed, there's a possibility that they are Auto loading at the tight 4-4-4-12 timings. Manually loosen them to 5-5-5-18. Those timings are in the order of CAS Latency - tRCD - tRP - tRAS, although your board may call them something different (just post a screen shot or another video of your timings options and we can help, but they're usually the first 4 anyway). OCZ memory is very picky about the tRAS value (the 18 in 5-5-5-18). Most memory run at either 4-4-4-12 or 5-5-5-15, but OCZ is usually only stable at 4-4-4-15 (DDR2 800) and 5-5-5-18 (DDR2 1066). The tRAS does not have a big impact on performance so don't be afraid to loosen (loosen means increase it) that a little more.

You'll also want to set the command rate to 2T (options are 0T 1T 2T). And set the tRC to something over 22 (like 23, 24, or 26). There might also be an option for tRFC. If so, there should be four tRFC values, labeled tRFC0, tRFC1, tRFC2, tRFC3 representing each of your four memory slots. Make sure they're all set to the same value, like 105ns (or the next highest number if it's still not stable at 105ns).

Any other timings just leave on auto. If you need help with these, another video showing your timings options, and then individually clicking on each to show us the options available to each timing would be very helpful.

2) Your memory voltage may be too low. The option is usually called DRAM voltage but might go by other names. Look up your specific memory set and find out what voltage it needs, then set your DRAM voltage to that value (or maybe even 0.05v higher). Right now your memory may not be receiving the juice it needs to run at the higher speeds.

Finally, it's possible that one of your sticks just cannot operate at the advertised speeds, timings, and voltage. So if you try everything above and it still doesn't work, then try running your computer at the proper timings, voltage, and DDR2 1066 speeds with just one stick of memory in at a time. Test both like this to see if maybe there is a problem stick.

EDIT: The memory's required voltage and 4 most important timings are usually on the sticker on the memory, so just pop open your case and take a look.


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## Rik

thanks for helping but,,, just watch the vid i didnt find any timing options like you were talking about


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## sccr64472

You pulled up the submenu for it, but you just escaped out of it. The advanced ram configuration was asking you which memory stick you wanted to play with. They're usually labeled Vdimm0 and Vdimm1, but yours were labeled slightly different. Select Both and you should be able to manually change the latencies.
Edit: I just watched it again and your are labeled DCT0 and DCT1. Select both to change the timings on both sticks.


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## djsi38t

Yes and also go to dram voltage and take it off auto and set it to 2.1 or whatever your ram's voltage is suppose to be.


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## Rik

so maye its voltages or a psu issue and now ill try the voltages thank you so much! this is a big help


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## durch

Quote:


Originally Posted by *Rik* 
thanks for helping but,,, just watch the vid i didnt find any timing options like you were talking about 




Ok, first things first, did you look at the sticker on your memory to find the rated timings and voltage? If not, please do that and let me know what it says, because there's many 2x2GB DDR2 1066 kits from OCZ and some use different voltages and timings.

Second, I see your DRAM voltage is still set to Auto, not a good idea. Once you check the sticker for the voltage, manually set it to that in the DRAM voltage option (probably 2.1v, but could be anywhere from 1.8v - 2.2v depending on which set you bought).

As for the timings, when you went into the menu called "Advance DRAM Configuration", did you see the "DRAM Timing Mode" option? It's the first option. Change it from Auto to DCT 0, I think that will open up more options for the timings. According to this thread, you should get the following options (or something similar):

CAS Latency (CL) = 5 CLK
TRCD = 5 CLK
TRP = 5 CLK
tRTP = [Auto]
TRAS = 15 CLK
TRC = [Auto]
tWR = [Auto]
TRRD = [Auto]
tWTR = [Auto]
tRFC0 = [Auto]
tRFC1 = [Auto]
tRFC2 = [Auto]
tRFC3 = [Auto]

That alone (and changing your DRAM voltage) may be enough to make it work, but we may have to manually set some of those other timings. If there is a way to change the tRAS from 15 to 18 do it. You may also want to try selecting DCT 1 instead of DCT 0 and see what that does. Again, the videos are a great help, plz keep them coming.

EDIT: Oh wow totally missed that there was a page 8 to this thread haha, I was going off your first response to my response. Yea from your videos looks like my hunch was correct, and with sccr's input I now understand the DCT 0 and DCT 1 thing, it's for the different modules. Definitely make sure you use the "both" option.

Your timings looked great. You might want to manually loosen the tRFC values to something like 105ns (or looser). Make sure you loosen all of the tRFC values (0, 1, 2, 3), and that they're set to the same value. Technically you only have to loosen the 2 that are occupied by your memory, but it doesn't hurt to adjust all 4.

And I still don't see any videos of you manually setting the voltage, that's easy to change and will certainly give you problems if it's too low. Plz look up what voltage your memory needs. I'm guessing 2.1v but I can't be certain, it depends on the IC's used in your memory and again, OCZ uses a lot of different manufacturers so we can't say for sure without you checking.


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## Rik

I added a pic of the ram sticker and it says 5-5-5 @ 2.2v ( no fourth number )
Also, I haven't seen anything in the bios regarding tRFC 0-3 and I've tried both sticks individually. Neither will run at 1066


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## durch

Quote:


Originally Posted by *Rik* 




I added a pic of the ram sticker and it says 5-5-5 @ 2.2v ( no fourth number )
Also, I haven't seen anything in the bios regarding tRFC 0-3 and I've tried both sticks individually. Neither will run at 1066

Yea there is no way your motherboard is running the RAM at 2.2v. That's considered "dangerous" to most IC's, so I highly doubt Auto is giving them the juice they need. That's really weird that none of the voltages are accessible, and there doesn't appear to be any option that can be changed to make them accessible. Usually motherboards have an option like "Voltage Control" that defaults to Auto but can be changed to Manual, opening up those options.

It may be a "hidden option". I think with some motherboards... once in the BIOS, hold ctrl and press F1, it sometimes opens up "hidden options". Basically some BIOS makers try to protect you from yourself. Give that a try. If that doesn't work, can you make a video of you opening all other options in that Cell Menu? Like maybe the HT Config has some weird options in it or something. I doubt it, but worth a peak. Also, have you tried looking in the "Standard CMOS Features" and "Advanced BIOS Features" menus? They might have a voltage control option hidden in them somewhere.

There's got to be a way to give yourself access to the voltages, we just need to figure out how.


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## Rik

after booting and running for about 5min it bsod'd i think it has something to do with the timings which i do not know how to manage . im almost there >.< i can taste it lol


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## durch

Oh man... pressing the + or - key? Really? Haha... I knew there was a way to change the voltages, that's a little ridiculous. Well glad we got that taken care of. Any instability you're experiencing now is likely from the overclock you just haphazardly threw on your CPU lol. Put that sucker back at 3.0GHz and make sure you're stable. If you are (pass a 12 hour Prime 95 blend test with 4 threads) then consider overclocking it a bit. But make sure you have proper cooling for it if you overclock, and make sure you manually set the CPU voltage if you overclock. You'll have to do a little research on safe voltage for that chip and KEEP AN EYE ON TEMPS. If you're using a stock cooler you really won't be able to overclock much at all without seeing temps go through the roof.


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## Rik

ive set everything back to defaults and then tried to set the ram speed and,,, no luck
i do however have my cpu overclocked to 3.7ghz @ 1.475v so at least out of all this i can say i learned how to better overclock my cpu by failing to set my ram timings correctly lol
overall i think that was the best ( crash ) course i've ever had


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## dms1

Having some trouble trying to apply these numbers to my application, can someone give me a nudge in the right direction? I've got a set of Kingston KHX2133C9D3T1K2/4GX 2x2GB 2133MHZ. and a Phenom X2 BE 955.

THe 955 is sitting at 4ghz on a multiplier of 20. the ram is being rated at 1600mhz from the nf980-G65 motherboard i have. how do I get the memory to 2133mhz? I have not seen any divider info on sticks of this speed.


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## gamer30

I'd give rep, but I still don't understand. It doesn't help that my mobo shows the dividers as 1:1, 1:1.2, 1:1.25, 1:1.5, 1:1.66, 1:2. I'm quite bad at maths so it doesn't help. Also when I punch in things like 3200/5 = 640 I get confused. When I set my CPU to 320(mult 10x) = 3200, and use 1:1.25 setting I get 800 RAM.

I don't even know what I'm saying. I'm using DDR2 800, and my multi is 10x (C2D E6700.) The more I read the more confused I get, and the charts don't help. I want to get a decent speed of around 3.0GHz and not fudge up my memory. Can anyone give me advice???


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## durch

Quote:


> Originally Posted by *gamer30;14212197*
> I'd give rep, but I still don't understand. It doesn't help that my mobo shows the dividers as 1:1, 1:1.2, 1:1.25, 1:1.5, 1:1.66, 1:2. I'm quite bad at maths so it doesn't help. Also when I punch in things like 3200/5 = 640 I get confused. When I set my CPU to 320(mult 10x) = 3200, and use 1:1.25 setting I get 800 RAM.
> 
> I don't even know what I'm saying. I'm using DDR2 800, and my multi is 10x (C2D E6700.) The more I read the more confused I get, and the charts don't help. I want to get a decent speed of around 3.0GHz and not fudge up my memory. Can anyone give me advice???


Well your problem is you have an Intel Core 2 Duo CPU, and this memory guide is for memory being used with an AMD CPU.


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## durch

I suppose I could be helpful still...

Ok, as this guide says DDR stands for "double data rate" meaning it transfers data on the rise and the fall of the signal. So DDR2 800 memory is NOT running at 800MHz, it is running at 400MHz. Well, it wants to run at 400MHz, that's what it is rated for.

Your E6700 runs at the following settings by default:
FSB: 266 MHz
CPU Multi: 12x

You said it is running a 10x multiplier, did you change that? It should be 12x by default. Well at a 266MHz FSB, you would need to multiply the 266 by 1.5 to get to 400MHz, which is what your DDR2 800 wants to run at to be at stock speeds. So if you don't overclock, you would want these settings:

FSB: 266MHz
CPU Multi: 12x
FSB : DRAM - 1:1.5

That would have your system running the E6700 at it's stock speed of 3.2GHz, and run your memory at it's stock speed of 400MHz (DDR2 800 speeds).

The problem is if you overclock the FSB, it will increase the CPU speed and the memory speed. This means you're overclocking two parts at once, so if the system becomes unstable, you won't know whether it is the CPU or the memory that is causing issues. So if you overclock, set the FSB : DRAM to 1:!. This will severely underclock your memory, allowing you to push your CPU as high as it can go. Once your CPU is maxed out (and stable with good temps) you can try increasing the FSB : DRAM ratio to get the memory running faster, or you could leave it at 1:1 because memory speeds don't impact total system performance that much, and after the overclock the memory should be running fairly close to DDR2 800 speeds anyway.

Also, make sure you manually set the memory voltage to what the product packaging listed, and manually set the four main timings as well (i.e. 4-4-4-12, 5-5-5-15, etc)


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## gamer30

Quote:


> Originally Posted by *durch;14212705*
> I suppose I could be helpful still...
> 
> Ok, as this guide says DDR stands for "double data rate" meaning it transfers data on the rise and the fall of the signal. So DDR2 800 memory is NOT running at 800MHz, it is running at 400MHz. Well, it wants to run at 400MHz, that's what it is rated for.
> 
> Your E6700 runs at the following settings by default:
> FSB: 266 MHz
> CPU Multi: 12x
> 
> You said it is running a 10x multiplier, did you change that? It should be 12x by default. Well at a 266MHz FSB, you would need to multiply the 266 by 1.5 to get to 400MHz, which is what your DDR2 800 wants to run at to be at stock speeds. So if you don't overclock, you would want these settings:
> 
> FSB: 266MHz
> CPU Multi: 12x
> FSB : DRAM - 1:1.5


My board only goes up to 10x. From what I understand, Intel bus is "quad pumped" meaning the rated FSB is 4x the FSB setting. The stock value is 1066, which is 266 x 4 = 1066 (1064 really, because it's actually 266.5)

FSB: 266.5
CPU: 10x
CPU clock: 2665
FSB: DRAM = 1:1.5 = 1066

These are the stock speeds taken directly from Intel:


Spoiler: Warning: Spoiler!



http://img232.imageshack.us/img232/8845/e6700intel.jpg



My MOBO actually automatically OCs the CPU by 3%. It actually runs 2720MHz and 1088 (272FSB) at stock values unless I manually lower it.
Quote:


> That would have your system running the E6700 at it's stock speed of 3.2GHz, and run your memory at it's stock speed of 400MHz (DDR2 800 speeds).
> 
> The problem is if you overclock the FSB, it will increase the CPU speed and the memory speed. This means you're overclocking two parts at once, so if the system becomes unstable, you won't know whether it is the CPU or the memory that is causing issues. So if you overclock, set the FSB : DRAM to 1:!. This will severely underclock your memory, allowing you to push your CPU as high as it can go. Once your CPU is maxed out (and stable with good temps) you can try increasing the FSB : DRAM ratio to get the memory running faster, or you could leave it at 1:1 because memory speeds don't impact total system performance that much, and after the overclock the memory should be running fairly close to DDR2 800 speeds anyway.
> 
> Also, make sure you manually set the memory voltage to what the product packaging listed, and manually set the four main timings as well (i.e. 4-4-4-12, 5-5-5-15, etc)


My current settings are:
FSB: 320
CPU multi: 10x
CPU clock: 3200MHz
FSB: DRAM 1:1.25 = 800

Later, I set the FSB: DRAM to 1:1 and changed the multiplier to 8 so I could get 400 FSB, plus DDR2-800 @ 800. The new clock speed was 3200MHz (3.2GHz) and the rated FSB was 1600MHz. This resulted in lower scores in PCMark05. In fact the scores were lower than even the CPU running at the stock values (see above.) Stock my score was 7022; in my current setup it's 7779; with my CPU and FSB: DRAM set 1:1 with 400FSB and 3200MHz I scored under 7000 (it was 68xx - i don't recall the last two numbers.)

I don't get why, but maybe someone else does. Perhaps AMD and Intel are two totally different worlds. Your information was still helpful to me, at least it got me thinking and trying different settings.


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## durch

The 400MHz FSB with the CPU at 3200MHz should have produced the best results. I think you may have two problems. A) You're using PCMark05. Why not try a more modern benchmarking tool? B) Your "stock" settings are not stock. Your CPU runs a 12x multiplier stock. Your board cannot support that, which makes me wonder if your board is complete junk, because that is very odd. You might have so other issues going on if the board you're using isn't quality.

But a _real_ stock E6700 at 266 x 12 = 3200 versus a 400 x 8 = 3200 should see better performance at the higher 400MHz FSB. But the difference won't be very noticeable. The real performance gains come from running the CPU at faster speeds. And I'm not talking some tiny little 3% overclock, I'm talking a real overclock. Push that CPU to its limits!


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## gamer30

Quote:


> Originally Posted by *durch;14236666*
> The 400MHz FSB with the CPU at 3200MHz should have produced the best results. I think you may have two problems. A) You're using PCMark05. Why not try a more modern benchmarking tool? B) Your "stock" settings are not stock. Your CPU runs a 12x multiplier stock. Your board cannot support that, which makes me wonder if your board is complete junk, because that is very odd. You might have so other issues going on if the board you're using isn't quality.
> 
> But a _real_ stock E6700 at 266 x 12 = 3200 versus a 400 x 8 = 3200 should see better performance at the higher 400MHz FSB. But the difference won't be very noticeable. The real performance gains come from running the CPU at faster speeds. And I'm not talking some tiny little 3% overclock, I'm talking a real overclock. Push that CPU to its limits!


I could be wrong about this, as I usually am. I thought when I bought it that the stock speed was 2670MHz, not 3200MHz, and the newer E8xxx series was 3GHz+. I'm going to double check that just to make sure. In the meantime, I'll give your suggestions a try. Which PC Mark should I run? I'm afraid to push it much higher because I already hit up to 66*C when using intel stress test. I tried to get it to 3600MHz but couldn't boot windows. The highest I put the VCore to was 1.38v I think, where I'm currently at 1.35v. I'm thinking about investing in a better cooler than this Gemini II because it's just not doing the job.


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## durch

Quote:


> Originally Posted by *gamer30;14246975*
> I could be wrong about this, as I usually am. I thought when I bought it that the stock speed was 2670MHz, not 3200MHz, and the newer E8xxx series was 3GHz+. I'm going to double check that just to make sure. In the meantime, I'll give your suggestions a try. Which PC Mark should I run? I'm afraid to push it much higher because I already hit up to 66*C when using intel stress test. I tried to get it to 3600MHz but couldn't boot windows. The highest I put the VCore to was 1.38v I think, where I'm currently at 1.35v. I'm thinking about investing in a better cooler than this Gemini II because it's just not doing the job.


Oh ok you have the older version of the E6700. The newer Wolfdale's are 3.2GHz: link Confusing naming schemes, I hate when companies do that.

PCMark Vantage would be the newest edition.


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## alexan_e

I have created a small excel spreadsheet that can calculate the memory divider, you can use it in your Android to make easy calculations about the resulting RAM frequency based on the bios speed setting.



DDRdividerCalc.xls 28k .xls file


Alex


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