My Intel Core i5-10400F reaches about 100°C even when total CPU usage is only around 50%. At idle, it typically sits between 50–56°C at roughly 3% usage. I recently cleaned the PC and replaced the thermal paste because of the high temperatures. The cooler is the Intel E97379 stock cooler, and the motherboard is an MSI B560M PRO-VDH. This was my first time applying thermal paste, so I'm unsure whether the cooler is making proper contact or whether I applied the paste correctly. Could the stock cooler, poor case airflow, or an installation issue explain these temperatures? What should I check first?
4 Answers
The Intel stock cooler is generally only just adequate for this processor. It can keep the CPU within its thermal limits when everything is ideal, but poor case airflow, dust, old paste, or imperfect contact can quickly push temperatures toward 100°C. Try running the system with the side panel removed; if temperatures drop significantly, improve the case airflow. Also check that all four cooler pins are fully locked into the motherboard.
Those temperatures are not ideal, even though the processor is designed to reduce its speed when it reaches its thermal limit. The simplest long-term fix is replacing the Intel stock cooler with a decent tower cooler, assuming it fits your case. Before buying one, still verify the stock cooler is mounted correctly and check that the fan is spinning at the expected speed.
If the temperatures were already reaching 100°C before the repaste, the paste probably wasn’t the only problem. That points more toward the stock cooler being insufficient, a mounting problem, or poor airflow inside the case. Monitor individual core temperatures and CPU frequency while testing, since 50% overall usage can still place a heavy load on some cores.
Since this was your first repaste, I’d start by reinstalling the cooler. Completely clean the old paste from both surfaces, place a small pea-sized amount in the center of the CPU, and mount the cooler evenly without twisting it excessively. Make sure the mounting pins are properly engaged and that the fan is connected to the CPU_FAN header. A little extra paste is usually harmless, but the cooler must make firm contact with the heat spreader.
The exact amount of paste isn’t extremely critical as long as it doesn’t prevent the cooler from sitting flat. The important parts are complete contact, even mounting pressure, and making sure none of the push-pins are still partially unlocked.