Thermal paste and CPU cooler: properly cooling your CPU

An poorly cooled processor means a PC that throttles: frequencies drop, gaming performance collapses, and the fan runs constantly. The good news is that correctly applying thermal paste and installing your CPU cooler is within everyone's reach, provided you follow the right method. Here is the complete guide, applicable to 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 cooler appear smooth, but under a microscope, they are covered with micro-imperfections. Without thermal paste, these gaps trap air, which is a very poor conductor of heat. The paste fills these gaps and ensures heat transfer between the CPU and the radiator.

You need very 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 builds, lifespan of 3 to 5 years
• High-performance pastes (€10 to €15): a few degrees gained on hot-running CPUs (Ryzen 7, Core i7 and above)
• Liquid metal: reserved for experienced users — electrically conductive, corrosive on aluminum, to be avoided for a first build

Step 1: Preparing the surfaces

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

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

Step 2: Applying the thermal paste

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

• The central dot: a pea-sized amount in the center of the IHS. The pressure of the 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) covers the elongated surface better.

Errors to avoid:

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

Step 3: Installing the cooler

On Intel LGA1700

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

On AMD AM4

Many coolers attach directly to the motherboard's original plastic hooks — this is the case for the Wraith included with some Ryzen chips. For a tower cooler, you usually remove these hooks to use the original backplate with the included mounting kit. Beware of the famous AM4 "suction effect": if you remove a cooler, do it when the CPU is warm (after a few minutes of load) and by twisting it slightly, so as not to rip the processor out of its socket.

On AMD AM5

AM5 shares the same mounting spacing as AM4: most AM4 coolers are compatible. The backplate is integrated into the socket, which simplifies installation. Since the CPU is held by a retention frame, the risk of it being ripped out no longer exists.

Connecting the fan

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

Step 4: Checking temperatures

Upon first boot, enter the BIOS for a preliminary check: at idle, a properly installed CPU runs between 30 and 45 °C depending on the model and ambient temperature. Under Windows, install HWiNFO64 or HWMonitor and run a load test (Cinebench R24, 10 minutes):

Note: Ryzen 7000 processors on AM5 are designed by nature to reach around 95 °C under heavy load — this is not an installation fault if the frequencies remain stable.

When to renew your thermal paste?

Quality paste lasts 3 to 5 years. Signs of dried-out paste: temperatures that climb gradually over the months, fan becoming increasingly noisy under equal load. A renewal costs €10 and 20 minutes of your time.

Conclusion

A careful cooler installation means a PC that is quieter, more stable, and retains its performance over time. If you prefer to start with an already assembled and tested machine, DSGate PCs are built in France with cooling adapted to each processor and temperature-checked before shipment. Discover our ready-to-use gaming PC configurations.