I've suffered with overheating on many occasions with my BPPC, but never because of the 040... It can be left as it is, no heatsink or fan and it will function perfectly... although I have fitted a HS+Fan to mine. Where my problems have been are with the PPC itself. I have a 160mhz 603e. The problems I had was mainly due to the thermal compound drying up, so replaceing that and it fixes it, and ive had the fan die on me too, but thats since been replaced. If the cards looked after and its fairly well ventillated you shouldnt experience any overheating at all...