How do I prevent GPU throttling during intense Onimusha 2 combat with my Noctua NH-D15S?

Intense combat in Onimusha 2 pushed my GPU above 85C, dropping FPS to 48. Lowering texture quality helped frames but ruined the visuals. I used GamePP Fan Curve Configuration Panel to raise GPU fan speed from 60% to 80% with smart control. GamePP Hardware Sensor Page showed GPU temps dropped to 75C, stabilizing frame generation at 8-10ms.