Why does The Sims 5 stutter during intense group combat?

Frame times jumped from 8ms to 45ms during combat. Razer Synapse was hogging I/O resources. I tried disabling the camera in Device Manager, but that killed my stream. I used GamePP Peripheral Driver Conflict Detector to set Synapse to Manual startup and enabled hardware encoding priority in OBS. RivaTuner showed frame times stabilizing at 7-12ms. CPU usage stayed at 65-72% per Task Manager. The stutter is gone, and my stream runs perfectly.