i'm having a strange problem. i had my Q6600 overclocked to 3.2ghz and prime95 was running stable with very reasonable temps. later i began having problems with lockups while web browsing, so i reduced my clock speed to normal. the lockups kept happening. i ran prime95 while at normal clock speed (2.4ghz) and started getting errors after 20-30 minutes. i have round off checking enabled, and am running the large FFTs torture test on all 4 cores. why would i be getting errors at normal clock speed? temps were low. i tried taking out one DIMM, then swapping for the other. no change. doesn't seem to be a memory issue. i don't get it. any advice appreciated...

You're suppose to run small FFT's for 8hours. After that, run the blend test for 12hours.

i fail to see how that's relevant to this thread.

Prime95's small FFT's test and the blend test. The small FFT's are to check for cpu stability while the blend test checks for the stability of the ram. If both passes for at least 8 hours, it's not the cpu or ram that's causing your issues.

Perhaps you should read the guide here on OCing, whether or not you're OCing.