My PC periodically throttles the CPU even during medium workloads. The clock speed drops to around 550 MHz and then recovers in less than a second, repeating roughly every 10 seconds depending on the load. HWiNFO shows that each drop coincides with the VRM MOS temperature reaching about 123°C and Thermal Throttling (PROCHOT EXT) being triggered.
The CPU is only around 65°C and the GPU is around 60°C when this happens. Removing the case side panel did not make much difference, and the case airflow seems reasonable. Even when the system is idle, the VRM MOS temperature sits around 88°C.
Could the temperature sensor be faulty, or are these temperatures a sign that the motherboard needs to be replaced? My system uses a Gigabyte A520M K V2 motherboard, a Ryzen 7 5700X, an ARCTIC Freezer 7X CO, and an Inno3D RTX 4070 SUPER.
2 Answers
Your tower-style CPU cooler may not be moving much air across the VRM heatsink area, and this motherboard does not provide much VRM cooling of its own. A cooler that directs some airflow toward the socket and power stages could help, as would improving the fan layout around the CPU area.
Still, given the idle temperature and the fact that a direct fan only lowers load temperatures to around 98°C, I would treat that as temporary mitigation rather than a fix. A reasonably equipped B550 board, such as a Gigabyte B550M DS3H, MSI B550M Pro-VDH WiFi, or ASUS Prime B550M-A, should handle the 5700X more comfortably.
Those VRM temperatures are genuinely too high, especially the roughly 88°C idle reading. The board has a fairly basic VRM design without proper heatsinking, so a Ryzen 7 under load can push the power circuitry hard enough to trigger PROCHOT and force the CPU down to its minimum clock speed.
As a temporary test, aim a small fan directly at the VRM area. If the temperature drops significantly, that confirms the power circuitry is overheating rather than the CPU sensor being wrong. However, getting down to about 98°C with the fan still is not a proper long-term fix. Replacing the motherboard with a better-cooled B550 model would be the sensible solution.
I tried an external fan pointed directly at the motherboard, and the VRM temperature fell to about 98°C during medium workloads. That confirms it helps, but it is still much too hot, so I agree that replacing the motherboard is the better long-term solution.
The direct fan did reduce the temperature to roughly 98°C during medium load, so airflow clearly makes a difference. Unfortunately, that is not low enough for me to consider it a permanent solution.