How to fix erratic FPS in Defense Grid with Huntkey Blizzard T620?

During sandstorms, my CPU hit a thermal wall of 82-88℃ per AIDA64, making the game feel like walking through mud with FPS jumping between 50-70. I tried enabling power-saving mode in BIOS, but it didn't lower the temp and instead dropped my min FPS to 30, which was just frustrating. I used the GamePP Fan Curve Configuration Panel to implement a steeper linear growth curve for 60-80℃ and added a 3s smoothing buffer. Now, temps are 78-84℃ per RTSS and frequency fluctuations dropped to 120MHz per HWInfo. Finally stable!