A little confused about how memory OC works - Overclock.net

garsh0p · 08-22-08

so i'm planning to upgrade my system with a GA-P35-DS3L and a E7200. i plan to do some slight overclocking.

i'm confused at how RAM speed factors into the whole FSB overclocking.

stock speed on a E7200 is 266FSB right, so memory would run at 266 x 2 = 533mhz? if i overclocked the fsb to, lets say, 320, would the memory run at 640 mhz?

i'm trying to decide what memory speed i need to buy, but i'm having trouble understanding how memory speed relates to FSB.

thanks for the help guys!

pauldovi · 08-22-08

You got the basic idea.

The memory ideally runs in a 1:1 ratio with the FSB, which is exactly what you were working out in your post. However you can also choise to run your memory in different ratio's such as 2:3, 3:4, and 2:1.

With a 2:3 ratio, your FSB might be 333 and your memory would be 999Mhz.

When purchasing your memory you want to consider several things. CAS Latencies is important as is the voltage. DDR2-1000 CL5 @ 2.2V is not better than DDR2-800 CL4 @ 1.8V. You can also put 2.2V into the DDR2-800 CL4 memory and get the DDR2-1000 out of it, but probably at a lower latency!

So also consider the CAS latency and the voltage when making your memory purchase.

Monst3r · 08-22-08

this is one thing im completely noob at.. Have no idea how the ram mhz works..

Arakasi · 08-22-08

Quote:

Originally Posted by The Vector Kid

Lesson time!

Your FSB is read from your motherboard, which has a QDR (quad data rate). This means that it takes a base number and multiplies it by four to get its FSB. So in your case, 1250 / 4 = 312.5. This base number is what controls the rest of your components. Your CPU will run with a speed of base x CPU multiplier and your RAM will run with a speed of base x memory multiplier.

Now RAM, being DDR (double data rate), also has a base number. You can get it by dividing its speed by 2. Your RAM is running at 1150 MHz, so 1150 / 2 = 575 MHz. That's your RAM's base number.

FSB:RAM ratio is determined by comparing the base number from your CPU/motherboard and the base number from your RAM. For a 1:1 ratio these numbers are the same; i.e you'd want your RAM to have a base number of 312.5, or a rated speed of 312.5 * 2 = 625 MHz.

Your ratio right now is 312.5:575, which is like 25:46. So go ahead and lower it a little, so it's synced up with the rest of your stuff. I guarantee you'll see more stability with less NB voltage.

TVK pointed this out earlier today and i thought he was right on the ball with explanation.... hope it helps you.

Source :

http://www.overclock.net/intel-cpus/...ml#post4424984

Monst3r · 08-22-08

not sure what i should change tho.. to be honest forgot what ram i have lol i know its old dm9 crucial ram forgot wat moel tho..

Urufu_Shinjiro · 08-22-08

Quote:

Originally Posted by Monst3r

not sure what i should change tho.. to be honest forgot what ram i have lol i know its old dm9 crucial ram forgot wat moel tho..

CPU-z should tell you what the SPD rated speeds are.

Monst3r · 08-23-08

says 400mhz?

Urufu_Shinjiro · 08-25-08

Quote:

Originally Posted by Monst3r

says 400mhz?

Then it's DDR2 800.

razr7 · 08-26-08

u overclock the ram with the divider

if u have 800mhz ram then u are running at 400x2

if u change the divider to 2.4 then the ram will run at 400x2.4 so u will have 960mhz rams

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A little confused about how memory OC works

08-22-08	#3 (permalink)
Monst3r GoSu^ Join Date: Aug 2008 Location: The best.. Aussie mate! Posts: 2,151 Rep: 256 Unique Rep: 165 Trader Rating: 0	this is one thing im completely noob at.. Have no idea how the ram mhz works..

08-22-08	#5 (permalink)
Monst3r GoSu^ Join Date: Aug 2008 Location: The best.. Aussie mate! Posts: 2,151 Rep: 256 Unique Rep: 165 Trader Rating: 0	not sure what i should change tho.. to be honest forgot what ram i have lol i know its old dm9 crucial ram forgot wat moel tho..

08-23-08	#7 (permalink)
Monst3r GoSu^ Join Date: Aug 2008 Location: The best.. Aussie mate! Posts: 2,151 Rep: 256 Unique Rep: 165 Trader Rating: 0	says 400mhz?

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