Thermal Grease (or thermal interface material, TIM) is an extremely high heat-transferring insulating silicone gel or grease containing some form of conductive metal particles. It is used as an interface between a microprocessor and a heat sink, or a water block in case of liquid cooling, to improve heat dissipation from the processor and reduce its temperature.
The conductive pastes are the more effective of the two. They feature a much higher heat transfer capacity than the non-conductive pastes and are made up of materials like silver, copper or aluminum. They are harder to apply evenly though and must be applied very carefully to ensure that the paste doesn’t make contact with any of the pins or electrical components of the circuit board as this could cause malfunction. Conductive pastes also tend to be more expensive.
Regardless of the type of conductive paste, all need to be carefully applied and the process can seem intimidating for beginners. It’s important to clean both the heat sink and the processor with isopropyl alcohol wipes before starting. Ensure that the pins are free of old paste and that there isn’t any dust or debris trapped on either surface as this will interfere with the proper transfer of heat.
Once the processor is cleaned, it’s time to apply the paste. A pea sized drop is sufficient for most processors. Use a business card or similar to spread it evenly across the metal die of the processor, being careful not to get any on any other part of the chip as it will be conductive and fry your CPU if it happens to make contact.