This is on the stock HSF at the default Vcore. I've had it up to 3.78 GHz but it was pushing 70 degrees C under load @ 1.5v Vcore. At this speed it runs at 3 degrees C over default 2.8 which is around 61.5C. I have the memory at 5x FSB. Ran it for 8 hours Prime95 and then played HL2 for 2 hours. Not a glitch in it. I was surprised.