Why does Black Myth: Wukong stutter on the Maxsun B850M board?

Entering Huaguoshan caused immediate stuttering as the VRM hit 85C. I tried adding a heatsink, but it failed and increased noise. Using GamePP Hardware Sensor, I remapped the fan curve from 1500 to 1800 RPM at 80C. AIDA64 showed stable 72-78C temps and frame times dropped to 8-10ms.