Copper has a thermal conductivity of 400 W/mk, where as Aluminum is only 237 W/mK.
Copper will heat up and cool down almost twice as fast as Aluminum for this reason, which makes it a more optimal material for heatsinks.
answered Aug 29 '10 at 17:56
Copper because it transfers heat better than aluminum. You going to get better cooling with copper.
answered Aug 29 '10 at 17:53