My PC started becoming unreliable a few months ago. Pressing the power button would often do nothing, although it sometimes started if I switched the power off for a few seconds and then tried again. I recently replaced both the case and the power supply, but the startup problem remains. Now, whenever the computer does start, the CPU temperature keeps climbing after only a few minutes—even while sitting in the BIOS—until the system shuts itself down. I replaced the thermal paste a few weeks ago and added another case fan. The CPU is a Ryzen 7 7800X3D with a Forgeon Azoth 360 ARGB liquid cooler, and the graphics card is an RTX 4080. The cooler's protective sticker was removed, so I'm unsure whether the issue is the cooler, its mounting, the motherboard, or something else.
2 Answers
The startup failure may be a separate issue. Replacing the case and power supply does not rule out the motherboard, a loose front-panel connection, or a short from a misplaced standoff. Test it with the motherboard outside the case using only the CPU, one RAM stick, cooler, and power supply, and briefly bridge the power-switch pins with a screwdriver. Reseat the 24-pin and CPU power connectors and inspect the socket for damage. However, don’t keep running it while the temperature climbs—solve the cooler or pump problem first, because repeatedly reaching the thermal shutdown limit can cause more damage and make diagnosis harder.
Since the temperature rises even in the BIOS, this is almost certainly a cooling problem rather than Windows or a software setting. With a 360 mm liquid cooler, check that the pump is actually running, that its SATA or motherboard power cable is connected, and that the pump reports a reasonable speed in the BIOS. Also verify that the radiator fans spin and that the cooler is mounted evenly with the correct AM5 hardware. If the pump has failed or the block is not making proper contact, the CPU can shoot to its thermal limit within minutes. Try a known-good air cooler if you have access to one; that will quickly separate a cooler problem from a CPU or motherboard problem.
The CPU is the part overheating. The system worked normally for more than two years before this started. I confirmed that the cooler’s protective film had been removed, but I haven’t yet checked whether the pump is reporting a speed.