CPU coolers are heat sink assemblies with integral fans that provide optimum cooling performance, often for specific processors. As electrons flow along the pathways in computer chips, resistance transforms some of their energy into heat. Dissipating this heat protects sensitive electronic components and increases their reliability and life expectancy. Larger heat sinks hold more heat than smaller heat sinks because of the relationship between surface area and the ability to dissipate heat radiantly. To help increase surface area, CPU coolers use integrated fans with directed fins to achieve specific airflow geometries. As air flows over the fins, heat is moved away from the CPU and to the surrounding area.