Why does Defense Grid drop to 55 FPS during sandstorms?

I felt totally defeated when the blinding sandstorms hit; my frame rate plummeted from 110 to 55 FPS, killing the flow. I tried setting the fan mode to full speed in the BIOS, but while temps dropped 3℃, the resonance noise made my whole chassis shake—it was just annoying. I then used the GamePP Fan Curve Configuration Panel to set a step-up gradient for the 75-85℃ range and pushed the peak to 1500 RPM. Now, core temps converge to 76-82℃ per AIDA64, and frame times are a stable 8-11ms via RTSS.