Why does my FPS drop from 60 to 20 in Crimson Desert?

I've had enough of this low-end motherboard's thermals; in Crimson Desert, the FPS suddenly crashes from 60 to 20 for minutes at a time. I first tried adding a small fan inside the case blowing directly at the board; while it dropped temps by 10 degrees, the drops still occurred randomly per HWInfo64, which made me furious. I used the GamePP Fan Curve Configuration Panel to lower the trigger to 40℃ and locked speed at 2000 RPM. Cinebench R23 showed VRM temps at 85-90℃ per AIDA64 to backup.