Answer to: Brass or copper heat sink?Copper is more expensive as it has much higher thermal conductivity. Apple probably wanted to use less copper in their products to be more cost effective. Most of the time they vary between Copper and Brass (or Aluminum) because it is only used for what creates a lot of heat (things like the processor). If you're doing work that takes a lot of wattage then Copper is a necessity for the efficiency of your computer, but usually it's fine with Brass. The guy that sold it to you did you a favor, I'd advise keeping it.