I've mentioned this in numerous posts, including once again just yesterday. Your machine isn't "freezing" because of the processor or the heat or anything hardware related. Just a hunch, but I'll bet your're running Windows 98 or ME. Am I right? I've experienced regular lock-ups during renders on a Intel Pentium 3 1Ghz. I've never locked up a single time on my AMD Athlon XP 1600 running Windows XP. I'm 99.9% certain that your problem is caused by your operating system. The solution is to step forward into the 21st century and upgrade to Windows XP (Windows 2000 will also likely clear up the problem)