Why does my Noctua NH-D15S fail to prevent CPU throttling in Hitman 3 crowded areas?

Sneaking around in 4K Ultra made my CPU feel like a space heater, with temps climbing to 92℃ in just two minutes. The NH-D15S default profile is way too quiet and conservative for this load, leading to core temps bouncing between 95-98℃. I tried a 'Turbo' software mode, but the fan whine at 1500 RPM was basically mental torture, echoing through the whole room. I eventually manually locked the PWM signal to a steady 80% and bumped my case intake airflow by 20%. Real-time monitoring showed temps drop from 98℃ to a more manageable 82-86℃, and my FPS stabilized from a chaotic 40-60 range to a steady 55-62 FPS. I noticed some slight vibration when I first locked the speed, but re-seating the fan clips killed the noise. Power draw is now steady at 130-145W with temps staying around 75-81℃. I exported the logs to verify the timestamps, and the fans are holding a rock-solid 1400-1600 RPM.