Reviving this old thread just to share my experience. I built my first system with an Atlon 2400+ on a Gigabyte motherboard. It was actually the first time ever I install a heatsink over a cpu and I put it the wrong way. Bad idea. When booting for the first time, I went in the BiOS to check system health and make sure everything is fine. CPU temp was raising and raising but at this point, I didn't know what were the normal operating temps for a cpu so I just stayed there hoping it will stop raising, haha. According to the BiOS, temperature hit 110C and then the heat protection kicked in the system went off.
I removed the heatsink and saw that the cpu changed color a little bit. Put the heatsink right, booted again and everything is fine. Can't believe the cpu isn't dead. It's been more than a year now and that system is still running smooth.
Now, yes, I know a Gigabyte motherboard that really sucks when it's time to shut off at the right time.
.fs.