Why does GTA VI drop from 70 to 35 FPS with DeepCool AS500 Plus?

While speeding through busy streets, my frame rate plummeted from 70 to 35 FPS, making the driving experience incredibly frustrating. I tried enabling power-saving mode to reduce heat, but while temperature dropped 5℃, the frame rate crashed further to 28 FPS, which was completely counterproductive. I used the GamePP Fan Curve Configuration to aggressively increase the speed gradient to 90% for the 65-85℃ range per AIDA64. RTSS showed frame times stabilizing at 14-18ms, and CPU temperature remained at 78-84℃ per GamePP.