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DDR2 RAM Dividers

127K views 46 replies 29 participants last post by  Hephasteus 
#1 ·
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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#2 ·
Stickied, because this is some amazing work that will help solve quite a few threads I'veseen.
Great work CWell!
 
#8 ·
Quote:

Originally Posted by thealmightyone View Post
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.
 
#9 ·
Nice work
 
#11 ·
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.
 
#15 ·
Quote:

Originally Posted by CWell1337 View Post
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!!
 
#16 ·
Quote:

Originally Posted by Tatalebuj View Post
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 View Post
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.
 
#18 ·
Irrelevant!
The memory controler only works with whole integers.
 
#20 ·
Quote:

Originally Posted by The Duke View Post
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
 
#23 ·
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?
 
#24 ·
Quote:

Originally Posted by Stalker View Post
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.
 
#26 ·
THANK YOU!!! At last, I can see the light!
 
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