I made the change from XP to 7 at Christmas. Yesterday I made the decision to try to push my overclock a bit further on my Q6600. It's been stable at 3.2GHz for ages, but seeing some people here put much higher voltages through the chip than I have made me want to try again for 3.5GHz or so. I upped the vcore two steps (I knew one step wouldn't do it) and set my clock to 3.4GHz, then tried IBT for 8 passes. Didn't pass IBT at that vcore or the one up from that. I was about to start pushing NB and SB volts too, but I noticed that in my last IBT test my temps had gone way higher than I was comfortable with, so I clocked back to my old vcore and 3.2GHz. Now, here's the oddity: I ran IBT again to make sure all was still well. It passed okay, but my temps were far higher than the last run under XP. Same vcore, same clocks, exact same system, case, system temp, everything, but: IBT under XP: Max temps on cores: 67-67-65-63 Max PWM temp: 60C System temp: 30C IBT under 7 (64-bit): Max temps on cores: 75-75-73-73 Max PWM temp: 79C System temp: 29C I used compressed air to blow some dust out of my case, but it didn't make any difference (I keep it fairly well-dusted anyway, so I didn't really believe that could account for such a rise). This is a huge leap in temps. The only variable that's changed in between the tests is the OS. Is this 8C difference really just down to the 64-bit OS allowing IBT to test with more memory? Any other explanation?