I'm researching for one of my student TAs - he's currently running a Q6600 OC'ed to around 3.52 Ghz - ran the torture test on Prime95 and passes 24 hours, BUT for some reason, if the computer is on IDLE-ing for a day or so, it'll BSOD... thoughts?
What test is it passing and for how long? Really you should be running the test for at least 10 hours, although most instabilities will make themselves known fairly quickly. It sounds like a RAM thing to me. Try lower clock/loosening timings on his ram. The blend test in P95 tests a fairly wide range of components so see if it will pass that for a reasonable amount of time.