What is Thermal Paste?

Thermal paste (also known as thermal compound, thermal grease, or TIM—Thermal Interface Material) is a thermally conductive substance applied between the CPU (or GPU) and the heatsink. Its primary function is to improve heat transfer from the processor to the cooling system.

CPUs and heatsinks aren’t perfectly smooth—they have microscopic imperfections. Even the most precision-machined components will have tiny air gaps when mated together. Air is a poor heat conductor, and this is where thermal paste comes in. It fills those gaps, ensuring efficient contact and optimal heat dissipation.

If you look at heat spreaders on CPUs or the cold plates on AIOs or Air Coolers, you'll see microscopic gaps that allow air to be trapped. Due to the low thermal conductivity of air, these small gaps can reduce the heatsink's cooling capabilities.

Therefore, it is important to use a thermally conductive material, such as thermal paste, to fill these gaps to ensure that heat is transferred efficiently.

Not all thermal pastes are created equal. Understanding the different types can help you choose the best one for your build:

• Metal-based: Offers excellent thermal conductivity but can be electrically conductive (use with care).
  
• Ceramic-based: Non-conductive and beginner-friendly, though slightly less efficient than metal-based options.
  
• Silicone or carbon-based: Balance between performance and safety; often used in pre-applied stock coolers.
  
• Liquid metal: High performance, but electrically conductive and not suitable for all coolers or surfaces (can damage aluminum heatsinks).

Applying thermal paste isn’t complex, but technique matters:

1. Clean surfaces with isopropyl alcohol and a lint-free cloth.
2. Apply a small amount (pea-sized or a thin line) in the center of the CPU.
3. Install the heatsink/cooler directly, using even pressure to spread the paste without air bubbles.

For a more detailed explanation, read our article on how to apply thermal paste.

Thermal paste isn't permanent. Over time, it can dry out or degrade, especially in high-heat environments. Consider reapplying if:

• You’re upgrading or reseating your cooler.
• Your CPU temperatures have increased unexpectedly.
• It’s been more than 2–3 years since the last application.