I upgraded an older prebuilt system from an Intel i5-10600K to a Ryzen 7 5800XT with an ASUS ROG Strix B550-F Gaming WiFi II motherboard. The system worked normally for about a week, but now the CPU quickly rises past 100°C even while sitting in BIOS and then shuts down. I reapplied the thermal paste using a pea-sized dot in the center, and the AIO cooler is connected to the CPU_FAN header. The cooler seems to shift slightly even though its mounting screws feel fully tightened. When I gently pressed the cooler against the CPU, the temperature immediately dropped from around 79°C to 49°C, then climbed again when I let go. The AIO is about five years old. What should I check?
3 Answers
The AIO pump may have failed, especially since it is around five years old. Check BIOS hardware monitoring to see whether the pump reports an RPM and whether its vibration or sound seems normal. It should be powered and configured to run at full speed, either through the AIO_PUMP header or an appropriate pump-controlled header. If the pump is not running, the cooler will not move heat away from the CPU.
Inspect the underside of the cooler for a protective plastic film, confirm the AM4 mounting hardware is correct, and make sure the cold plate is sitting flat. A pea-sized amount of paste is fine and does not need to be manually spread. Also verify that the radiator and tubes are positioned sensibly, since trapped air can interfere with pump operation, but the immediate temperature change when pressing the block points more toward mounting pressure or a failed pump.
The cooler should not move at all once it is mounted. That temperature drop when you press it down strongly suggests the cold plate is not making proper contact with the CPU. Recheck the mounting brackets, spacers, standoffs, and screws, and tighten the cooler evenly in an X pattern. Do not keep running the system until the mount is secure.
That makes sense. The caps on the mounting screws are tight, but I may need to check the double-ended standoffs and make sure the correct AM4 hardware is installed.
If the radiator is mounted at the front, having the tubes at the bottom is generally preferred. A top-mounted radiator is also fine. More importantly, the pump should be running and the block must be firmly clamped against the CPU.