Heat sink Thermal CPU Compound PC Grease Paste.
Thermal compound is necessary to create a reliable transfer of heat from your computer's processor to its heat sink to keep your CPU from overheating. This thermal grease can be used on the rear side of the heat-sink which has no thermal pad. It will improve the heat dissipation of your processor.
The thermal transfer compound improves the effectiveness of CPU coolers by thermally bonding the CPU to the heat sink. This ensures that the heat sink and fan can work at their full capacity to remove the harmful heat away from the CPU, and prevent burnout or heat damage.