A thermal compound is a paste, which improves the heat transfer between the processor (CPU) and the CPU cooler. There are various types of pastes which can have a different composition depending on the manufacturer. The classic thermal compound consists for example of silicone oil and zinc oxide. Other pastes may contain constituents of copper, graphite, aluminum or silver. However, there are also silicone-free thermal pastes that consist of a thermoplastic material. In addition to the thermal compound there are also thermal pads that have the same function.