Thermal paste is a vital cog in the PC building wheel and often overlooked (perhaps because it’s not as exciting as some other parts of your build). But, correctly applying thermal paste can prevent overheating and sudden shutdowns.

The surface of a CPU is covered in tiny grooves and gaps that allow air to slip between the processor and the heat sink. The paste gets into these spaces, fills them up, and creates an air-tight seal. This allows the heat sink to pull more heat from the CPU. The best thermal pastes are easy to apply, spread evenly, and stay stable after application without leaking or cracking. They also have good thermal conductivity and are electrically insulating.

Different manufacturers produce a wide variety of blends, each with its own characteristics. Some are based on ceramics, others on metals, and still more use a combination of materials. Some have a high price tag while others are very inexpensive. The best choice depends on the type of CPU and your skill level when it comes to reapplying the paste.

Some pastes are very difficult to work with and are not suitable for beginners. They may require a great deal of attention and concentration during application, and even small accidental spills or drips can short out the circuitry of the computer. Others are simple enough for any experience level and do not contain micro-metallic particles that would be dangerous if they made their way into the pins of a chip.