How to Apply Thermal Paste

Choose a high-quality thermal paste. Most basic thermal pastes contain silicon and zinc oxide. More expensive options include thermally conductive materials like silver or ceramic. While silver or ceramic-based pastes are more efficient at heat transfer, basic thermal paste is usually sufficient for most needs.

• If you plan to overclock your computer, opt for thermal paste with silver, copper, or gold as the primary component. These metals are among the best thermal conductors widely used in cooling products.

Clean the CPU and heatsink surfaces. Use a cotton swab or ball soaked in isopropyl alcohol to gently wipe the CPU and heatsink surfaces. The higher the alcohol concentration, the better. 70% is sufficient, but 90% is even better if available.

Smooth the heatsink and processor surfaces if necessary. Ideally, these contact surfaces should be perfectly flat, eliminating the need for thermal paste. If the heatsink base is uneven, you can wet sand it with fine-grit sandpaper. Unless optimal cooling performance is your goal, this step is optional.

• Thermal paste is designed to fill gaps and imperfections on contact surfaces. Since modern manufacturing cannot produce flawless surfaces, thermal paste remains essential.

Place a small drop of thermal paste in the center of the heatsink base. The drop should be smaller than a grain of rice. If someone suggests using a "pea-sized" amount, that’s too much and could cause the paste to spill onto the motherboard.

• For round-base heatsinks, spreading the thermal paste evenly across the surface is unnecessary.

Attach the heatsink to the processor. Align and place the heatsink evenly onto the processor. The thermal paste will naturally spread across the contact surface, forming a thin, even layer that fills gaps without leaving excess.

• When exposed to heat, the paste will spread thinner and wider toward the edges. Using a small amount is crucial for optimal performance.

Avoid removing the heatsink after installation. It’s difficult to verify if the thermal paste has been applied correctly. Removing the heatsink breaks the seal created during installation, forcing you to repeat the entire process, starting with cleaning off the old paste and applying a new layer.

Reattach the fan to the motherboard. The CPU fan cable should be plugged into the designated CPU fan slot, as these often support PWM functionality, allowing the computer to automatically adjust fan speed without changing voltage.

Restart the system. Check if the fan is spinning. Access the BIOS by pressing F1 or Del during the POST phase. Verify that temperatures are normal: the CPU should remain below 40°C at idle, and the GPU should also stay within safe limits.

Apply thermal paste to the heatsink base. For square-base heatsinks, applying thermal paste is slightly more challenging, as simply placing a drop and pressing the heatsink down won’t ensure full coverage. Various methods are used, and here we’ll cover the most popular ones:

• Line Method – Apply two thin, parallel lines of thermal paste on the heatsink base. The distance between them should be one-third the width of the processor, and the lines themselves should be about one-third the processor’s width in length.
• Cross Method – Similar to the Line Method, but the lines intersect to form an “X.” The length and thickness of the lines remain the same.
• Spreading Method – The most common and effective approach, though slightly more labor-intensive. Apply a small amount of thermal paste to the heatsink base, then use a plastic glove or bag to spread it evenly across the surface. Ensure the entire contact area is covered and the layer isn’t too thick. In most cases, the paste should just be enough to cover the metal beneath.

Install the heatsink. For the first two methods, ensure the heatsink is installed evenly to allow the thermal paste to spread across the entire surface. For the third method, you MUST tilt the heatsink slightly during installation to prevent air bubbles from forming. This is because the thermal paste is often spread too thinly to prevent air bubbles when pressed down.

Reconnect the fan to the motherboard. The CPU fan cable should be plugged into the CPU fan slot, as it typically supports PWM functionality, enabling the computer to automatically adjust fan speed without altering voltage.

Restart the system. Check if the fan is spinning. Enter the BIOS by pressing F1 or Del during the POST phase. Verify that temperatures are normal: the CPU should remain below 40°C at idle, and the GPU should also stay within safe limits.