No problem with the lower-end chips from AMD here (K6, Duron and now a low Athlon), and I cannot say I had any trouble with heating either: all three withstood an average summer here with no trouble at all (temperatures going up to 35 C in the room containing the computer), despite having only average fans. Then again, I never used the biggest CPUs, and those probably heat up more... but British Columbia should have cooler summers than France.
