I went to Best Buy to figure this out. The laptops there run for hours on end so about 6 in the evening you can answer your question firsthand. Be aware that it's not specific to just the selected CPU. The laptop make/model (design) can make either a winner or loser in this comparison.
I'd like to know witch one between thoses two CPU heats the more? A AMD 64 bits Athlon mobile(low voltage) or a dothan 1,7 GHz centrino?
Also, do you know a site where there is a comparaison between a P-M and an AMD cpu temperature?