Why does Call of Duty 2 drop from 144 to 60 FPS during combat?

During intense urban combat, I felt anxious as my frame rate plummeted from 144 to 60, causing obvious visual jolts. I tried enabling Low Latency mode in the drivers; while response improved, the frequency of drops didn't decrease, proving it couldn't solve the hardware bottleneck. I used the GamePP Resource Scheduler to set the core process priority to Realtime. RivaTuner showed frame time converged to 7-12ms, GPU temp stayed 66-72℃ per AIDA64, and VRAM temp hit 82-88℃ per HWInfo, ensuring the game runs smooth.