Quote Originally Posted by Bo_Fox View Post
Although aluminum fins do pretty well with heatpipes, copper is just better if you have at least a 2000+ rpm fan blowing directly on it. I do not know exactly what the threshold would have to be (airflow CFM and air pressure) in order for copper fins to be more efficient than aluminum, but let's just say 2000 rpm for most heatpipe heatsinks out there. Zalman's hugely popular CNPS9700 would be nowhere nearly as good if the fins were aluminum instead of copper. On that heatsink, aluminum fins would perform just as well as copper only if it came with a super-quiet fan (say, 1500 rpm max). For fan-less heatsinks, aluminum is a god-send!
At any fan speed, copper is a better material for heat transfer vs aluminum. I have done term papers on this, it's thermodynamic fact. My Zalman did come with a low speed fan(1500rpm is in no way at all super-quiet, you don't see that until you go below 1000rpm), and it worked fine. Unless you can show us some testing results proving your assertion, it's just wrong to make these kind of claims about copper v. aluminum. The heat transfer from the material to the air is a function of the air and temperature delta, not a function of the material.