First, the idea that the P4 runs cooler than the Athlon XP is a farce. It's a myth. It's like saying that "aluminum cases cool better". It has no foundation in fact what-so-ever.

Second, the Pentium M is a mobile CPU. It was designed from the ground up to have low power consumption and heat output. The Mobile Athlon XPs and P4ms also run very cool. Right now, my 2600m in the KX7, which is sitting on my desk, has a SLK-800 with a 50cfm Sunon fan on it. I'm ducting outside air onto the heatsink, not because it needs it, but just for the hell of it. It's like 65*F outside right now. The CPU is at 2.2GHz and 1.45v, it's under full load, and it's running at 25*C. The board temperature is also 25*C.