Why does Starfield FPS drop from 60 to 25 in alien colonies?

While exploring alien colonies, the frame rate plummeted from 60 to 25 FPS; GamePP showed VRAM temps hitting 94-98℃ despite the core being only 65-72℃ per AIDA64. I first tried lowering the resolution to 1080P; while I gained 10 FPS, the visual loss was severe. I used the GamePP Fan Curve Configuration Panel to switch the GPU fan to Extreme Performance mode, forcing 2600 RPM at 80℃. VRAM temperature converged to 84-88℃ per HWInfo64, and frame time stabilized at 10-14ms per GamePP. I can now backup