Help with P5Q Mobo

do you have your RAM "linked" in the BIOS? if your FSB is 1600 it would be 1:2 (800 DDR)

btw, if you haven't noticed, your overclocked! and a good one at that. unlink the RAM and set it to 1033, test with prime95 for stability and watch the temps.

Not quite true loonian.

aw is overclocked and a pretty decent one also. FSB freq is 400 MHz. FSB clock is 1600 MHz. Mem freq is 400 MHz. Mem clock is 800 MHz. FSB:RAM ratio is 1:1.

Leave all your settings alone and stress test with Prime95 small fft's. If you encountered any failures, increase the CPU core voltage a little.

At 3.6 GHz, you should be OK with the stock cooler.

About the RAM:
What you really have is DDR2-800 RAM that has been tested to run at the higher speed at a higher RAM voltage.

Your BIOS is reading the JEDEC #2 profile and using that to automatically set motherboard memory settings. If you want to use the EPP #1 profile, you need to increase the RAM voltage.

I recommend that you do not. Your best stability will occur at 1:1 and OC'ing RAM will give little extra performance anyway.
http://www.tomshardware.com/forum/251715-29-ratio-myth

thank you for those corrections jsc. the brain is having "one of those days".

i think its nap time  

Thanks for the advice, I've left things as follows:

FSB Freq 400MHz (3.6GHz)
Multiplier 9
DRAM 1066MHz
CPU voltage 1.29375v
RAM voltage 2.1v (you recommend against... should I revert to "auto"?)

but Prime95 keeps failing on one processor... I've read elsewhere on these forums that 3.6GHz should be easily possible on an E8400 even at stock voltage, so why might mine be failing at a bumped voltage? I have an aftermarket cooler, and when being stress tested temp never exceeds 52 degrees.

what would you recommend?