# DDR2 RAM Dividers



## CWell1337

I've been seeing a lot of questions on RAM and dividers lately, so I made up a chart of various DDR2 values based on RAM Dividers, FSB, and CPU Mulitpliers.


















Hope this is helpful to some.


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## Chipp

Stickied, because this is some amazing work that will help solve quite a few threads I'veseen.







Great work CWell!


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## rottenotto

Great job... I have a feeling that this chart's gonna find its way to quite a few forums....


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## <[email protected]> (CS:S King)

Can you make one for Intel? lol


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## CWell1337

I may get around to it eventually.


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## <[email protected]> (CS:S King)

meh.. o k thx cuz i be needin a chart you knows


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## thealmightyone

A little pocket calculator is much easier to use than loads of printed out charts.


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## CWell1337

Quote:


Originally Posted by *thealmightyone* 
A little pocket calculator is much easier to use than loads of printed out charts.

It's barely 2 pages of small charts and it was made for people who don't know how to do the calculations (or frankly are just too lazy lol). And if you wanted to print it out and cut out the chart for the multi you use, it would be easier than using the calculator.


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## The Duke

Nice work


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## foodforthemoon7

I have no clue what this is showing us... Anyone mind explaining what a ram divider is...


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## CWell1337

I will try to explain it to you in terms of your actual computer you have setup in your rig. I think that will be easier.

First of all, if I'm not mistaken, your CPU runs on an 11x multi correct? So you would look at the 11x table above. The left column is your FSB you have set in your BIOS. The top row are the "dividers" that you can set your RAM on in the BIOS (DDR2-400, DDR2-533, DDR2-667, or DDR2-800).

So let us say you have your PC OC'd to 2.64Ghz on an 11x multi. That would mean your FSB is set to 240Mhz. So, according to the table, you have 4 options on where to run your RAM (as far as speed is concerned).

If you set the divider to DDR2-400, your RAM would run at DDR2-480.
If you set the divider to DDR2-533, your RAM would run at DDR2-587.
If you set the divider to DDR2-667, your RAM would run at DDR2-754.
If you set the divider to DDR2-800, your RAM would run at DDR2-880.

So as I have said above, I made these charts, to be used by the people who don't know how to make the calculations to figure all of this out, or are just too lazy to do the work!

Hope that clears some stuff up.


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## Niko-Time

Very nice thread


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## Tatalebuj

Thanks for the chart, but I'm also quite new to the whole OC'ing scene. Someone posted a question about doing a chart for "intel", does that mean if I have a CD2 E6600 I won't be able to use the 9x multiplier chart to OC my Ballistix DDR2-800 (2gb) RAM?

Thanks,

Tata


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## stargate125645

What is the number next to the RAM speed? Like "400 /11"? Is that the denominator in the divider? It is a bit counter-intuitive the way that is organized. All the motherboards I've seen run the divider with respect to the FSB and not the CPU multiplier.


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## NecroshineX

Quote:


Originally Posted by *CWell1337* 
It's barely 2 pages of small charts and it was made for people who don't know how to do the calculations (or frankly are just too lazy lol). And if you wanted to print it out and cut out the chart for the multi you use, it would be easier than using the calculator.

Yes, I admit....I am one of the lazy ones. Love charts!! FTW!!


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## CWell1337

Quote:


Originally Posted by *Tatalebuj* 
Thanks for the chart, but I'm also quite new to the whole OC'ing scene. Someone posted a question about doing a chart for "intel", does that mean if I have a CD2 E6600 I won't be able to use the 9x multiplier chart to OC my Ballistix DDR2-800 (2gb) RAM?

Thanks,

Tata

That is correct. These charts will not be accurate if you are running an INTEL system. As for the why, well it's as simple as saying AMD =/= INTEL.

Quote:


Originally Posted by *stargate125645* 
What is the number next to the RAM speed? Like "400 /11"? Is that the denominator in the divider? It is a bit counter-intuitive the way that is organized. All the motherboards I've seen run the divider with respect to the FSB and not the CPU multiplier.

The number you are referring to is the divider number. In the example you listed DDR2-400 will run on an 11 divider if your CPU is running on an 11 multiplier.


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## Norse

Just curious but is it possible to get a updated version of this that includes half multipliers? ie 12.5 ?


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## The Duke

Irrelevant!
The memory controler only works with whole integers.


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## CWell1337

The Duke is right, as usual


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## Norse

Quote:


Originally Posted by *The Duke* 
Irrelevant!
The memory controler only works with whole integers.


Yea but im to lazy to work out what 2.5ghz will make the divider when using 667mhz ram


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## faisal

when to set timing of 1:1(amd)??
anybody please xplain


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## KRookie

really sexy!


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## Stalker

That chart confuses the crap out of me...can anyone do an example for me as simple as possible cuz I still don't understand where to use the multiplier and the fsb and the divider in the equation... what does the equation look like?

Does that mean that if I have my CPU multi on 12x, my FSB on 250, my mem divider set to 533mhz and my HT multi on 5x then I can run my CPU @ 3ghz, my memory on 667mhz and my and my HT freq on 1250mhz? Does this make sense at all?


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## The Duke

Quote:


Originally Posted by *Stalker* 
That chart confuses the crap out of me...can anyone do an example for me as simple as possible cuz I still don't understand where to use the multiplier and the fsb and the divider in the equation... what does the equation look like?

Does that mean that if I have my CPU multi on 12x, my FSB on 250, my mem divider set to 533mhz and my HT multi on 5x then I can run my CPU @ 3ghz, my memory on 667mhz and my and my HT freq on 1250mhz? Does this make sense at all?

Having you memory at 333MHz of a DDR2 667 setting will give your RAM about 83% of the CPU clock speed. I say about because the CPU multiplier screws with actual speed.
So for every 100MHz the CPU is OCed, the RAM will only increase @ about 83MHz.

Do remember, the CPU speed effects the RAM and HT, but the HT has nothing to do with the RAM speed set in the BIOS. The HT speed is directly related to only the CPU.

Do check out CPU-Z and the "Memory" section. It will display the actual raw RAM speed so you do have to double it to see the DDR2 speed.


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## durch

A couple months ago I wrote up some more details on the subject with examples. It's a longer read, but might benefit some of you still confused by the charts. DDR2 Memory Dividers Explanation with Examples


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## Stalker

THANK YOU!!! At last, I can see the light!


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## adramalech707

okay i am digging the chart







just got done printing it out, but i have one problem....i am trying to get 3.0ghz on a x2 4600+...now do to the chart i am trying for a cpu multiple of 12 and a fsb of 250...









now after that part i don't think i got it right because by what durch said in his thread about dividers i am thinking that having my memory at ddr2-800 is possible at 3ghz, i took 3000/6 = 500x2 = 1000









now i think i misunderstood something along the line....should i put the divide at ddr2-667 instead??









also, i don't have my memory at the epp standard, i have it at the motherboard default settings, which is 5-5-5-18 [email protected] 1.9volts or 2.1volts....but the epp settings for the memory is 4-4-4-12 2T @2.1volts

also i have increased the fsb and increased the vcore of the NB also increasing the cpu voltage to 1.5volts, but i am still getting a post error about the amount of mhz of the fsb...should i try and lower the ht from 5x to 4x to allow for a higher fsb???


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## llChaosll

Hey Adramalech, putting your ram frequency on 800 and putting your CPU Multi to 12 and HT to 250 will net you 3Ghz and your ram will be running at 1000 mhz. If you ram cant take the 1000 speed, simply reduce your ram frequency to 667 and your ram will be at 750mhz.
Try to find the highest your ram will go, then pick a multi that will work with both high ram frequency and cpu clock.
Hope that helps, always remember to change your HT Link Multi, you want to stay anywhere from 900-1100 HT.
To figure out your HT, simply multiply your HT Multi by your HT or as people would say FSB.
In your case if you use the above example then put your HT Multi to 4.
250X4 = 1000 HT.

GL!


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## SciaTica

So after reading this most informative post, what I have been able to glean from it is that:

If I want my memory to be OC'd to higher speeds, I should overclock my CPU using the Frequency rather than the Multiplier, therefore increasing my memory speed along with CPU rather than just the CPU.

AND

If my Frequency is set so high that it causes my memory to become unstable, I reduce the memory divider to re-stabilize it, kind of like the HT multiplier?

Thanks, SciaTica


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## WBaS

Quote:


Originally Posted by *SciaTica* 
So after reading this most informative post, what I have been able to glean from it is that:

If I want my memory to be OC'd to higher speeds, I should overclock my CPU using the Frequency rather than the Multiplier, therefore increasing my memory speed along with CPU rather than just the CPU.

AND

If my Frequency is set so high that it causes my memory to become unstable, I reduce the memory divider to re-stabilize it, kind of like the HT multiplier?

Thanks, SciaTica

Yep pretty much. Increasing your reference clock will increase both your cpu and memory. If you want to change your ram frequency you can either do it by changing your reference clock or divider.


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## Monst3r

im totally confused.. all i see are numbers.. So i went to the x9 multiplier chart then went to ddr2-800 then went to fsb 260 as it doesnt say 266 for my duo.. Then i went to the last number it says 936? what does this number mean.. Only thing ive never learnt with overclocking as my brain just wont pick up on it.. i really wanna learn this so i can push my rig and my future rigs to their limits


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## Monst3r

Like say if my fsb:ratio was 2:3 since i have a fsb of 266 i would 266/2=11 so my FSB ratio would be 266: (How do i work out this part of the ratio) totally confused


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## kpo6969

http://www.anandtech.com/mb/showdoc.aspx?i=3208&p=4


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## Monst3r

sorry but i still dont understand it dammit.. im gonna need a video or something lol


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## kpo6969

2 quick examples (getting late)
E8400 (333 FSB stock)
I run @ 3.6 = 400 FSB 
DDR2 ram 800mhz (400x2)
400mhz x2 (cpu) = 800mhz=400mhz x2 (ram) = 800mhz (ram) = 1:1 divider 800/800
400mhz x2 (cpu) = 800mhz=500mhz x2 (ram) = 1000mhz (ram) = 5:4 divider 1000/800


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## evilspongebob72

they way gigabyte do it is just easier

2, 2.4 ....


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## Monst3r

Quote:



Originally Posted by *kpo6969*


2 quick examples (getting late)
E8400 (333 FSB stock)
I run @ 3.6 = 400 FSB 
DDR2 ram 800mhz (400x2)
400mhz x2 (cpu) = 800mhz=400mhz x2 (ram) = 800mhz (ram) = 1:1 divider 800/800
400mhz x2 (cpu) = 800mhz=500mhz x2 (ram) = 1000mhz (ram) = 5:4 divider 1000/800


add me on msn [email protected] need some help big time lol


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## WBaS

Are you overclocking an AMD system or Intel? They do memory 2 different ways. These charts are meant for AMD ONLY and DDR2 memory. So lets say your using a x15 cpu multi and have your ram set as ddr2-800 in the bios. That means you need to use the last chart and the last column of the chart. At stock speeds, the AM2 chips use a FSB of 200. So now you look at the first row in the last column and should see 750. This means your ram is running at 750Mhz effectively. Now if you overclock your cpu by using a FSB of say 260, then your ram is now running at 975Mhz.

For Intel systems, things are a little different (at least until Nehalem core comes out). For Intel, their cpus use different starting FSB's and are "quad" pumped. For example, some chips have a 333FSB and are quad pumped (333x4= about 1333Mhz, for a total FSB). So if your fsb:ram ratio is set to 1:1, your memory will run at 1333Mhz. If you set your ratio to 1:2, then your ram will run at half the total FSB value (1333Mhz/2=667Mhz). Or if the ratio is set 2:3, your ram will run at 1333*(2/3)=889Mhz Now for the cpu speed... if your cpu uses a 9x multi, then your cpu will be running at 333x9= about 3.0Ghz.


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## noobdown

Quote:



Originally Posted by *WBaS*


Are you overclocking an AMD system or Intel? They do memory 2 different ways. These charts are meant for AMD ONLY and DDR2 memory. So lets say your using a x15 cpu multi and have your ram set as ddr2-800 in the bios. That means you need to use the last chart and the last column of the chart. At stock speeds, the AM2 chips use a FSB of 200. So now you look at the first row in the last column and should see 750. This means your ram is running at 750Mhz effectively. Now if you overclock your cpu by using a FSB of say 260, then your ram is now running at 975Mhz.


also if you refer to the chart. where each speed is the is a /#. if you take that number and devide it by your cpu speed, it will give you the speed your ram is running at. hience the divider.
example
3000mhz(cpu) divided by 8 = 375mhz. because it ddr times it by 2 = 750.


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## Monst3r

nevermind i worked it out.. DRAM Final Clockrate = (2 x FSB)/DividerExample, 2/3 divider @ 400 MHz FSB: (2 x 400 MHz)/(2/3) = 1,200 MHz


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## N2Gaming

Cwell who is the girl in your vader I tink I'm in wub


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## desertmonk

Bloody brilliant idea. How simple yet how useful is this for seeing RAM speeds at theoretical multi/dividers/FSB.

Thanks!


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## blackguard

needs a DDR2-1066 update D:


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## Gen

Well, I got bored and decided to make an updated chart that applies to the K10's and K10.5's.

If enough people request it, I'll make the chart go higher than 298 HTT, just a matter of tweaking the program I wrote to speed this up







.


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## Hephasteus

And then they went and put the DDR3 ram dividers in and made more complex dividers.


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## Gen

Quote:


Originally Posted by *Hephasteus* 
And then they went and put the DDR3 ram dividers in and made more complex dividers.

Not a bad idea, I should get the DDR3 chart done too







Smoke break out in the cold then I'm on it...

What is the standard dividers for DDR3, 1066, 1333, 1600? Should I go higher?

DDR3 memory dividers added above, 1066-2133.


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## Hephasteus

Quote:


Originally Posted by *Gen* 
Not a bad idea, I should get the DDR3 chart done too







Smoke break out in the cold then I'm on it...

What is the standard dividers for DDR3, 1066, 1333, 1600? Should I go higher?

DDR3 memory dividers added above, 1066-2133.

I think the AM3 uses pure /3 dividers.
533 = 1066 = 16:6 = 8:3 = (8 / 3 = 2.6666666) = 2.6666666


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