He he, no, it's correct. I'd refer you to Dave's article on AMDMB, but I still can't find it.
The copper is great for direct contact with the heat source, which makes it an excellent base for an HSF, but the Alu will give you more surface area, for the same weight.
Copper's thermal properties are so good, that air has a harder time getting all the heat out of it.
Now all this assumes that the Alu fins are in good contact with the copper tube. If one uses lead to solder the fins, you can forget about it: you might as well have copper fins because it won't make much of a difference.
Where's my MIG welder?
|