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Old 07-08-2008, 12:00 PM   #1
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Default FSB:RAM Ratios?

Hey,

My FSB is currently 450, and my RAM is @ DDR2 900. This means it's a 1:1 ratio, correct? I also wouldn't see any performance gains if I boosted the RAM to 1066, right?

Right now the RAM is at 5-5-5-15, and is rated for 1066. However, I saw in a lot of the newegg reviews that people lowered the timings to 4-4-4-12, and lowered the speed of the RAM to 800mhz.

Could I achieve 4-4-4-12 timings @ 900mhz, and do I simply change the timings, or is it a trial and error process like OCing your CPU?

One more thing:

Is 1.4125V ok for a X3350 quad? Also, CPU-Z and my ASUS program say that my CPU is only at 1.336V, why is this? I set it to 1.4125V in my BIOS. Does this mean I could potentially OC my X3350 even higher? (Right now it's at 3.6ghz) It's running @ 42C on load, so I have wiggle room :P
Thanks!
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Old 07-08-2008, 01:04 PM   #2
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Default Re: FSB:RAM Ratios?

Quote:
My FSB is currently 450, and my RAM is @ DDR2 900. This means it's a 1:1 ratio, correct?
Yes.
Quote:
I also wouldn't see any performance gains if I boosted the RAM to 1066, right?
Theoretically, no, especially not if you have to loosen the timings.
Quote:
Right now the RAM is at 5-5-5-15, and is rated for 1066. However, I saw in a lot of the newegg reviews that people lowered the timings to 4-4-4-12, and lowered the speed of the RAM to 800mhz.

Could I achieve 4-4-4-12 timings @ 900mhz, and do I simply change the timings, or is it a trial and error process like OCing your CPU?
At first, I normally leave the timings slack whilst I'm OC'ing the CPU so as to eliminate another variable, then once I've reached the max CPU OC, I lower the timings one by one (starting from the first) to the lowest value I can boot into Windows and complete a P95 blend test with. Once I've decided on the timings, I let the blend test run for 2 hours+ to check for stability.
Example: My timings are 5-5-5 etc etc. I start by lowering the first to 4, the system posts and boots into Windows fine and passes the 5 min stress test. Next, I lower it from 4 to 3, the system fails to POST, I set the value to 4 and proceed to lower the second and so on.
Quote:
Is 1.4125V ok for a X3350 quad? Also, CPU-Z and my ASUS program say that my CPU is only at 1.336V, why is this? I set it to 1.4125V in my BIOS. Does this mean I could potentially OC my X3350 even higher? (Right now it's at 3.6ghz) It's running @ 42C on load, so I have wiggle room :P
Thanks!
It depends on the "in Windows" reading. 1.4125V may be the BIOS setting, but it's once you're in Windows that you'll know the real value.
The difference between the idle voltage and the under load voltage is Vdroop. Less is better. I pencil mod my board to eliminate Vdroop. There may be one for the Rampage too, just do a little Googling.
Also make sure you do not go above 1.3V on the FSB termination. But this should not be a problem as my E3100 runs 4.2 @ 1.1V FSB termination.
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Old 07-08-2008, 01:58 PM   #3
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Default Re: FSB:RAM Ratios?

Quote:
Originally Posted by worshipme View Post
Yes.

Theoretically, no, especially not if you have to loosen the timings.

At first, I normally leave the timings slack whilst I'm OC'ing the CPU so as to eliminate another variable, then once I've reached the max CPU OC, I lower the timings one by one (starting from the first) to the lowest value I can boot into Windows and complete a P95 blend test with. Once I've decided on the timings, I let the blend test run for 2 hours+ to check for stability.
Example: My timings are 5-5-5 etc etc. I start by lowering the first to 4, the system posts and boots into Windows fine and passes the 5 min stress test. Next, I lower it from 4 to 3, the system fails to POST, I set the value to 4 and proceed to lower the second and so on.

It depends on the "in Windows" reading. 1.4125V may be the BIOS setting, but it's once you're in Windows that you'll know the real value.
The difference between the idle voltage and the under load voltage is Vdroop. Less is better. I pencil mod my board to eliminate Vdroop. There may be one for the Rampage too, just do a little Googling.
Also make sure you do not go above 1.3V on the FSB termination. But this should not be a problem as my E3100 runs 4.2 @ 1.1V FSB termination.
I'm not sure I entirely understood the last part, but for now, 3.6ghz is fast enough XD

I'm going to get my timings lower now Thanks for the advice.

Update:

I changed my CAS latency from 5 to 4, and it wouldn't even boot....what's wrong :S? Good thing my mobo has a reset CMOS button
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Old 07-08-2008, 02:12 PM   #4
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Default Re: FSB:RAM Ratios?

Quote:
I changed my CAS latency from 5 to 4, and it wouldn't even boot....what's wrong :S? Good thing my mobo has a reset CMOS button
Your memory simply can't POST with that setting. And you don't need to reset the CMOS every time. Just hold the power switch for 3-4 seconds.
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