In order to get the maximum cooling, you would want the heatsink to be as big as possible, in order to get the largest surface area, but keeping in mind other limitations such as space and weight. Traditionally aluminum has been used, but copper has become more popular because it absorbs and transfers heat faster. Unfortunately, cooper is a heavy element so installing a big heatsink entirely out of copper might become a risk for some systems motherboards due to the weight.

Some heatsink manufacturers have taken the approach of making only part of the heatsink out of copper, to try to get some of the benefits without making the heatsink too heavy. This is the case with the one being reviewed today, The Thermalright SI-97.

Thermalright SI-97