Radiation

Q equals the heat that is radiated; the more you radiate the better. e is a constant that pertains to the properties of a particular metal and the way it is manufactured. The symbol represents a property known as emissivity; the value ranges between 1 and 0. From the equation we can see that a value close to 1 is preferable to maintain beneficial radiation properties. The A stands for the area through which the heat is flowing, for our heatsinks, this would be the sum of all areas of the fins and the base to which they are attached. The first T stands for the temperature on the side that the CPU is touching the heatsink. The second T would be the ambient temperature, from this we can see that a lower ambient temperture would be desirable, as more heat would then be radiated.

One easy way to improve the radiative properties of a heatsink would be to make it black. They don't wear black clothing in the desert just for nothing. A fun thing called black body radiation makes this all possible. A black object absorbs a great deal of radiation, from which it gets its color. When temperature is taken into account, the color black also acts a good emitter of energy, in our case heat. Since our little heatsink will be the hottest thing around, black would be the ideal color for it.

Spray away

But don't go out and paint your heatsink black if you have one that is some other color; black heatsinks are manufactured by a process called anodizing. This process is a way by which to add an almost molecular layer to the object. Dipping your heatsink into a cup of paint will add far more paint, and in the end, the paint will act as an insulator - reducing the effectiveness of the heatsink.

In reality, very little heat is actually radiated away. Typically, the majority of the heat that is removed comes from sources other than radiation. Once we start dealing with absurdly high temperatures, this becomes more of a factor. For the moment, it'd be nice if the heatsink conformed to the equation, but it isn't necessary. The temperature differences we are dealing with are not great enough to affect the outcome of the performance of any heatsink to any appreciable level. Sorry for making you guys read all that stuff, but hey - knowing is half the battle!