Today's PC common CPU heat sink, whether mainstream or high-end products, almost all use such a structure: the structure of the contact with the CPU/GPU surface is made of copper, that is, we often say copper base, and the heat pipe fin or water-cooled fin is made of aluminum. The so-called "copper aluminum combination" said is such a structure, and the use of copper fin or copper water cooling radiator, that is, we commonly known as the "pure copper radiator" in the PC field can almost be said to be a flash in the pan, only in the earlier years ever appeared.

So why "copper aluminum combination" can become the mainstream design of PC heat dissipation? If you go to online search, gets the most that should be "copper and aluminum combination after comprehensive factors with the best balance", you can be as simple as size, weight, technology, cost, the heat efficiency and other aspects of comprehensive, even say, aluminum radiator efficiency is better than copper, copper heat faster, just Therefore, the combination of copper and aluminum is to combine the advantages of the two together, and the heat dissipation efficiency will be higher than the pure copper structure. All this seems plausible, but is it really the case?

In fact, the answer has been given by the Newton cooling formula Q=hAΔT in thermodynamics, Newton cooling formula is mostly used in the calculation of convective heat transfer, and the CPU heat dissipation is essentially to let the CPU heat transfer to the air through the radiator, the radiator itself will not generate heat, also can not eliminate heat, That IS TO SAY, the radiator needs to bear the "heat" is the CPU "heat", or call it total heat flow. As we have explained in our Super class article "Super Class (302) : What is Heat? (Part 2)", the energy used to drive the CPU will basically be converted into heat in the end, so as long as the CPU power consumption is unchanged, the total heat flow will not change, and the total heat flow is Q in Newton's cooling formula. A in the formula is the contact area between the radiator and the air. As long as the structure and size of the radiator are unchanged, the heat exchange area will not change, and the material of the radiator does not have any relationship; h is the heat transfer coefficient of the fluid, which is basically a constant value as long as the convection mode and the type of gas are constant.