Why does Forza Horizon 5 stutter during drifts?

I was helpless with drift stutter in Forza Horizon 5. I tried changing the GPU slot, but it caused hangs. I used GamePP BIOS Load Line Voltage Adjustment Wizard to raise voltage from 1.00V to 1.05V. In FurMark, voltage fluctuation dropped from 0.1V to 0.02V. Temperature stayed at 68-75℃ per GamePP sensors. The drifts are smooth now, and I can race without frustration.