Tom N0SS wrote: As I recall, general rule of thumb: If you can place your hand (finger) on the heatsink and leave it there for 5-6 seconds without screaming, it's getting 'warm'. ================= Isn't that the "general rule of the (blistered) thumb"? Isn't the function of the fan to cool the inside of the K2 and NOT the heatsink itself? Ron AC7AC K2 #1289