Definition - What does Heat Sink and Fan (HSF) mean?
A heat sink and fan (HSF) is an active cooling solution used to cool down integrated circuits in computer systems, commonly the central processing unit (CPU). As the name suggests, it is composed of a passive cooling unit (the heat sink) and a fan. The heat sink is usually made from a high-temperature conductive material such as aluminum and copper, and the fan is a DC brushless fan, which is the standard used for computer systems.
Techopedia explains Heat Sink and Fan (HSF)
A heat sink and fan is often used in modern computer systems to keep the processor cool. Without it, the processor could easily overheat and become damaged. Therefore, this combination is often found in most low- to mid-range computer systems, and even in high-end notebooks. However, for PCs and computer systems that boast a more powerful processor, a more powerful cooling solution is required, such as liquid cooling.
The heat sink is a thermal conductive material that quickly carries heat away from the processor. It is designed to have the greatest amount of surface area in a small volume of space, so aside from the flat contact surface the heat sink has many thin "fins" that facilitate heat dissipation through thermal convection, which means the heat is further carried away from the heat sink itself by air. Often the normal flow of air is not enough to allow for quick cooling, so a fan has to be added. Together, the HSF is the least expensive cooling solution available, with efficiency varying according to the heat sink design and fan power.