Thermal Paste and CPU Cooler: The Tutorial for Proper CPU Cooling

A poorly cooled processor means a throttling PC: frequencies drop, in-game performance plummets, and the fan runs constantly. The good news is that correctly applying thermal paste and mounting your CPU cooler is within everyone's reach, provided you follow the right method. Here is the complete guide, valid for Intel LGA1700, AMD AM4, and AM5 sockets.

Understanding the Role of Thermal Paste

The metal surface of the processor (the IHS) and the base of the CPU cooler appear smooth, but under a microscope, they are covered in microscopic imperfections. Without thermal paste, these crevices trap air, which is a very poor heat conductor. The paste fills these imperfections and ensures thermal transfer between the CPU and the heatsink.

You need little: the paste does not replace metal-to-metal contact, it complements it. Too much paste insulates instead of conducting, and can overflow onto the socket.

Which paste to choose in 2026?

• Classic silicone/ceramic-based pastes (€5 to €10): sufficient for most configurations, lifespan of 3 to 5 years
• High-performance pastes (€10 to €15): a few degrees gained on CPUs that run hot (Ryzen 7, Core i7 and above)
• Liquid metal: reserved for experienced users — electrically conductive, corrosive on aluminum, to be avoided for a first assembly

Step 1: Prepare the Surfaces

If you are replacing an existing CPU cooler, start by cleaning off the old paste. Use isopropyl alcohol (90% or more) and a microfiber cloth or lint-free paper towel. Gently rub until the IHS is clean and shiny, then let it dry for one minute.

For a new CPU, no preparation is necessary. Simply ensure that the processor is properly clipped into its socket and that the retention mechanism is locked.

Step 2: Apply Thermal Paste

Application methods are much debated, but tests converge: on a consumer CPU, the differences between correct methods are on the order of 1 to 2 °C. Remember these two simple approaches:

• The central dot: a pea-sized dot in the center of the IHS. The pressure from the CPU cooler spreads it evenly. Ideal for square CPUs (Intel, AM4).
• The line or double dot: on rectangular CPUs like Ryzen AM5, a thin vertical line in the center (or two small aligned dots) better covers the elongated surface.

Mistakes to avoid:

• Spreading with a spatula or finger: risk of air bubbles and uneven thickness
• Applying too much paste: it will overflow onto the socket when tightened
• Forgetting to remove the protective plastic film from under the CPU cooler base — the classic mistake of a first assembly, which leads to catastrophic temperatures

Step 3: Install the CPU Cooler

On Intel LGA1700

Most CPU coolers use a backplate that screws in behind the motherboard. Mount the standoffs, place the heatsink well-aligned on the CPU, then screw in a cross pattern: a quarter turn on each diagonal screw, gradually, until it stops. This cross-tightening ensures uniform pressure and even spreading of the paste.

On AMD AM4

Many CPU coolers attach directly to the motherboard's original plastic clips — this is the case with the Wraith included with some Ryzen CPUs. For a tower cooler, these clips are usually removed to use the original backplate with the supplied mounting kit. Be careful of the famous AM4 "suction cup effect": if you remove a CPU cooler, do so with the CPU warm (after a few minutes of load) and by twisting slightly, so as not to rip the processor from its socket.

On AMD AM5

AM5 uses the same mounting holes as AM4: most AM4 coolers are compatible. The backplate is integrated into the socket, simplifying installation. Since the CPU is held by a retention frame, the risk of pulling it out no longer exists.

Connecting the Fan

Connect the fan to the motherboard's CPU_FAN header (not SYS_FAN). Without a fan detected on this header, many motherboards refuse to start or display an error — this is a safety feature.

Step 4: Check Temperatures

On first boot, enter the BIOS for an initial check: at idle, a properly mounted CPU runs between 30 and 45 °C depending on the model and ambient temperature. In Windows, install HWiNFO64 or HWMonitor and run a stress test (Cinebench R24, 10 minutes):

Note: Ryzen 7000 on AM5 are designed to reach up to 95 °C under heavy load by design — this is not an installation defect if frequencies remain stable.

When to Replace Thermal Paste?

Quality paste lasts 3 to 5 years. Signs of dried paste: temperatures gradually increasing over months, fan becoming noisier at the same load. A replacement costs €10 and takes 20 minutes.

Conclusion

Careful CPU cooler installation means a quieter, more stable PC that maintains its performance over time. If you prefer to start with an already assembled and tested machine, DSGate PCs are assembled in France with cooling adapted to each processor and temperature-controlled before shipping. Discover our ready-to-use gaming PC configurations.