Thermal paste is a substance applied between a computer processor and a heat sink to improve heat transfer. It fills microscopic gaps and imperfections on the surfaces, ensuring better contact and efficient heat dissipation. This helps keep the processor cool, enhancing performance and longevity. There are various types of thermal pastes, including ceramic, metal-based, and silicone-based options. Each type has different thermal conductivity levels and application methods. Regular maintenance, such as reapplying thermal paste, can be essential for optimal cooling, especially in high-performance systems or older computers.