48*C max load on a P4 2.4GHz with 1.47v. Not all that great actually considering it is an all-copper heatsink. However, the shroud it has is useful and keeps case temps down A LOT because I have it jetting the air straight out of the back of the case. I think I may try to reverse the fans I have and actually have it suck outside air into the case over the CPU. That would raise case temps a bit though I guess..