copper costs more then aluminum no? so even smaller copper heatsinks would probably cost the same or more right?
why do pc's need copper heatsinks now? because they put out so much heat. if the g5 can get away with the aluminum heatsink for now, i don't really care. its got a straight line of circulation from the front of the case to the back of the case through the heatsink. airflow is not restrcted like on pc heatsinks where the fans have to blow straight down through fins towards a solid base. the efficiency has to be better as fans are not good at fighting back pressure, being that the g5 fans are in straight line series to boot boosts their efficiency to about max possible.
the fact is it works. you don't see g5's burning up or crashing because of heat. the o/s even controls the fans in advance when it predicts high heat output from certain activities. i'm sure they'll use copper in the future, i'm not sure how aluminum looks better then copper like you seem to be asserting. my guess is they are saving money.
you can't even see the heatsinks, they are shrouded, they could put copper ones in there under the silver cover wihtout changing the look anyways.
fact is most retail heatsinks that come with amd processors are still aluminum. guess their engineers are twits.