First, the heat transfer coefficient "Micro Cooling Fan" Copper is almost twice aluminum, but this does not mean copper heat sink cooling effect can be up to twice the aluminum radiator. Because the effect of the heat sink and the work is not only determined by the thermal properties of the material. Secondly, better thermal performance and can not make up for the shortcomings of copper market - higher prices. Again, the higher the density of the material also makes the quality of the copper heat sink is relatively heavy, which means higher static gravity. Finally, "Micro Cooling Fan" also unsatisfactory hardness of copper and some other "birth defects." Despite this, there are still part of the heat sink using a combination of copper and aluminum manufactured. The heat sink base mostly copper, and the metal fins are made of aluminum. Thermal conductivity higher than aluminum and copper, can be more uniformly transfer heat to the aluminum fins of the periphery. "Micro Cooling Fan" coefficient of thermal conductivity of aluminum itself is not infinitely large, there is a temperature gradient inside fins: the higher the temperature near the center fin assembly, close to the periphery around the lower temperature.