Searching the net the other day, I came across a chart with "critical temperatures". Critical temp for an Athlon64 is 65C. My 4000+ is at 35C idle and 45C at load with stock cooling and cpu fan at constant 3080rpm. With motherboard's temps at 40c and 45c idle/load. I noticed the ambient room temp has a lot to do with it too. On a cold day when the room temp is around 65F, the cpu was down in the 27C at idle, my room is usually in the mid 70's and then I see around 35C at idle on the CPU.