Why does the game stutter badly while I am harvesting crops?

Harvesting in Farming Simulator 25, I saw frame times jump from 10ms to 18ms. I maxed the fans manually, but the noise was unbearable and HWiNFO still showed 82-85℃. I used GamePP Fan Curve Configuration Panel to set 75% speed at 75℃. GamePP Hardware Sensor Page confirmed temps dropped to 72-75℃. The stutter is gone, and the settings feel right.