Civen Metal Material（shanghai）said pure copper has the best heat dissipation among the alloy copper. Generally speaking, the more pure copper has better heat dissipation.
Among the pure copper, brass copper, bronze copper, the pure copper has the highest purity . So it has the best heat dissipation.
Civen Metal Material（shanghai）said the heat dissipation material is copper .But it also focus of its shape, surface area, cooling fan features, and so on. While the material in not the most important.