I just had a system failure with my CPU running too hot. The PC World techs had replaced the CPU without applying new paste and it just got too hot and the PC shut down. As I had just had the PSU replaced I thought it meight be that cutting the power, but looking at temps in BIOS my CPU was going up to 69c. Of course I immediately shut it down and re-pasted it with Akasa paste/ I have ahd it running for a couple of hours now and the CPU wasn't fried by these extreme temperatures, and it now runs at 40-44c idle. So the moral is, if you take off the heatsink for any reason (especially if you used the conductant paste AMD put on it) clean off the paste from the CPU and heatsink and apply new paste before firing up the PC again. I hadn't really thought the paste made a big difference but it certainly seems to be crucial in cooling CPUs