How do I stop CPU downclocking in Digimon World: Next Order?

I saw massive frame drops in high-load Digimon scenes, with water temps hitting 55℃. I tried increasing the radiator fan speed, but it didn't help the liquid temperature. I used the GamePP Hardware Sensor Page to switch the pump speed from 1500 to 2000 RPM. HWiNFO recorded the water temp dropping to 48-50℃. This switch to higher pump speed kept my performance stable.