Thermal paste and thermal pads are both thermal interface materials used to improve heat transfer between two surfaces, typically a heat source (such as a CPU or GPU) and a heatsink. However, they differ in their composition, application method, and thermal conductivity.
Composition: Thermal paste, also known as thermal compound or thermal grease, is a viscous substance that contains a mixture of thermally conductive particles suspended in a silicone or metal-based compound. These particles, often made of materials like metal oxides or ceramics, help fill in microscopic imperfections on the surfaces, improving thermal contact. Thermal pads, on the other hand, are solid pads made of materials such as silicone or graphite, which are inherently thermally conductive.
Application: Thermal paste is typically applied as a thin layer directly onto the heat source, such as the CPU or GPU. It requires manual spreading or applying a small amount and relying on the pressure of the heatsink to spread it evenly. Thermal pads come pre-cut in specific sizes and shapes and are placed between the heat source and the heatsink. They are designed to conform to the surface irregularities and fill in gaps, providing a consistent thermal interface.
Thermal Conductivity: Thermal paste generally has higher thermal conductivity compared to thermal pads. The thermally conductive particles in the paste help facilitate the transfer of heat between the surfaces, allowing for efficient heat dissipation. Thermal pads, while still providing reasonable heat transfer, often have lower thermal conductivity compared to pastes.
Reusability: Thermal paste is usually designed to be a one-time application. Once applied and cured, it forms a stable interface between the surfaces and is not intended to be easily removed or reused. In contrast, thermal pads can be easily removed and repositioned, making them more convenient for situations that require frequent disassembly, such as when upgrading or changing components.
The choice between thermal paste and thermal pads depends on various factors, including the specific application, desired thermal performance, ease of installation, and reusability requirements. Thermal paste is often favored in high-performance applications where maximizing heat transfer is crucial, while thermal pads are commonly used in scenarios that require convenience, reusability, and where moderate thermal conductivity is acceptable.