Interesting subject, copper or Aluminum
From a heat conduction standpoint, I know copper is near top of the list. Aluminum is up there too, but from a dissipation standpoint, aluminum (from what I've observed) seems to top copper in popularity.
Case & point: Aluminum cores in rad's seem more in demand these days, not just because of material cost or weight.
Home baseboard heating: uses copper pipe to 'deliver' and aluminum fins to dissipate.
Computer core coolers: Uses copper to conduct the heat, aluminum to dissipate. Again, not because of cost or weight. (folks pay plenty for these and would be willing to pay more for better heat dissipation.)
There are good heat conductors, then there are good heat radiators. Obviously, conduction has a lot to do with it.
Note: I am not an expert at this, (That's why we have Tony :grin: ) just making an observation.