How do I fix physics engine lag in Shadow Blade Zero on Thermalright PS120 SE?

Cloud layer physics caused the frame rate to drop from 120 to 48 FPS. I tried Performance mode, but the E-Cores still lagged. I used GamePP to set Load Line Voltage to L3. Cinebench R23 score rose to 37200, and HWiNFO showed stable temps at 78-84℃.