After reading Crazed792's post, i pulled the fan on my athlon 2800xp under full load and it ran for 18 seconds then throttled down, then shut down. reattatched fan, rebooted. runs great.
Since the results were good, i just tried it on this machine, my athlon64 3200+ , which is overclocked by 200 Mhz, ran for about ten seconds then shutdown. reattatched fan, rebooted and everything is great.