What is a Thermal Compound?

A thermal compound or thermal paste is a sticky substance used to improve the heat conduction between a computer processor CPU and a heat sink. The primary purpose of applying thermal compound is to fill microscopic air gaps that exist due to imperfect surface flatness on both the heat source and the heat sink. These gaps can trap air, which is a poor conductor of heat, thereby reducing the efficiency of heat transfer.

The thermal compound helps direct heat away from the CPU. Without this compound, your CPU may overheat, possibly causing multiple problems.

Thermal compounds are made from a variety of materials that enhance their ability to conduct heat. These materials can include metals like silver or aluminum, ceramic particles, or silicon compounds. The choice of material affects the thermal conductivity, electrical conductivity, and ease of application of the thermal paste.

Types of Thermal Compounds

Thermal compound is used to improve heat transfer between a computer processor and a heat sink. Below are its types and applications –

Metallic Based Pastes

• What They Are: Pastes containing metal particles such as silver or aluminum.
• Heat Transfer: Offer high thermal conductivity.
• Considerations: Electrically conductive, requiring careful application to prevent short circuits.
• Examples: Arctic Silver.

Ceramic Based Pastes

• What They Are: Composed of non-metallic ceramic particles like aluminum oxide.
• Heat Transfer: Provide good thermal conductivity, safer for electronics.
• Considerations: Preferred for general use where electrical risks are a concern.
• Examples: Arctic MX-4, Noctua NT-H1.

Silicone Based Pastes

• What They Are: Use silicone oil with conductive materials.
• Heat Transfer: Generally lower in thermal conductivity.
• Considerations: Useful for less demanding applications.
• Examples: Often found in generic brands and pre-applied on some cooling components.

Carbon Based Pastes

• What They Are: Contain carbon or diamond particles.
• Heat Transfer: High conductivity, comparable to metallic pastes.
• Considerations: Non-conductive and excellent for high-performance needs.
• Examples: Thermal Grizzly Kryonaut, Innovation Cooling Diamond.

Liquid Metal Compounds

• What They Are: Alloys like gallium-indium that are liquid at room temperature.
• Heat Transfer: Extremely high thermal conductivity.
• Considerations: Can be corrosive to some metals and require careful handling.
• Examples: Thermal Grizzly Conductonaut.

How to Apply Thermal Compound?

To apply thermal compound properly, start by cleaning the surfaces of the CPU and the heat sink using isopropyl alcohol to remove any old paste or residue. Once the surfaces are clean and dry, apply a small pea-sized dot of thermal paste directly in the center of the CPU. Avoid using too much paste—a small amount is sufficient.

Next, carefully place the heat sink on top of the CPU, ensuring it sits evenly to spread the paste beneath it. Secure the heat sink according to the manufacturer’s instructions. This pressure will spread the paste adequately across the CPU surface. Finally, attach the heat sink fan connector to the motherboard. Double-check everything is mounted securely and correctly before turning on your computer.

Need of Thermal Compound on CPU

Thermal compound is essential for effective heat management in computers, especially between the CPU and its heat sink. This compound fills the tiny imperfections on the surfaces of the CPU and heat sink, which otherwise trap air, a poor conductor of heat. By eliminating these air gaps, thermal compound enhances the transfer of heat away from the CPU to the heat sink, thus preventing overheating.

Overheating can lead to reduced performance, system instability, and potentially damage the CPU. Using thermal compound ensures that the CPU operates within safe temperature limits, maintaining optimal performance and prolonging the life of the hardware.

What is a Thermal Compound? – FAQs

What is thermal compound used for?

Thermal compounds fill in microscopic gaps between the central processing unit /graphics processing unit (CPU/GPU) and the heat sink, ensuring better contact and maximizing heat transfer. Without thermal compounds, air pockets could form, leading to poor heat dissipation and potential overheating issues.

What is the composition of thermal compound?

Thermal paste consists of a base matrix and containing a thermally-conductive filler. Typical matrix materials are epoxies, silicones, urethanes, and acrylates. Fillers include carbon micro-particles, aluminum oxide, boron nitride, zinc oxide, and aluminum nitride.

Where is thermal compound applied?

Thermal compound is applied between the CPU or GPU and the heat sink to enhance heat transfer and prevent overheating.

Can you touch thermal paste?

Thermal paste is not toxic, but it can still cause irritation, allergy, or infection if it comes into contact with your skin, eyes, or mouth. It can also stain your clothes, furniture, or other surfaces. Therefore, you should handle thermal paste with care and caution.