Why does my Seagate FireCuda 540 1TB cause frame jitter in Khazan gunfights?

Aiming in Khazan felt like fighting a ghost. I uninstalled background apps and hit a black screen. I used GamePP Peripheral Driver Conflict Detector to find a webcam sync service hogging I/O. I disabled it. RivaTuner showed frame time dropping from 8-12ms to 5-6ms. This driver fix is essential to export your stable settings.