Why is frame generation time fluctuating between 12-28ms during aerial combat scenes in Victoria 3?

During aerial combat, I faced violent stuttering with frame times swinging from 12-28ms. I tried disabling the memory controller in Device Manager, but it caused a system crash. I used GamePP Peripheral Driver Conflict Detector to set RGB sync to manual and enabled hardware encoding priority. RivaTuner confirmed intervals stabilized to 8-11ms, and HWiNFO showed temps at 50-56℃. This exported a stable experience.