What is the primary role of thermal grease in computer assembly?

Thermal grease, often referred to as thermal paste, is primarily used to conduct heat away from the CPU, enhancing the effective thermal transfer between the CPU and the heatsink. The microscopic imperfections on the surfaces of the CPU and the heatsink can trap air, which is an insulator. Applying thermal grease fills those gaps, allowing for better contact and thus more efficient heat transfer. This is crucial for maintaining optimal operating temperatures for the CPU, which can help prevent overheating and ensure the longevity and performance of the computer.

The other options do not accurately describe the primary function of thermal grease. It is not intended to secure the CPU in its socket, nor is it designed for electrical insulation or aesthetic purposes. Its key role is specifically centered on heat conduction, making it essential for effective thermal management in computer assemblies.