Why does Final Fantasy XV stutter in Insomnia city areas?

I felt absolute despair when entering Insomnia; the periodic stuttering made the game feel like it was freezing. I tried cleaning all background software to free up space, but GamePP Sensor showed memory usage stuck at 96-99%, proving simple cleaning is useless against this bottleneck. I used the GamePP Resource Scheduler to set the game process priority to Realtime and fixed virtual memory to 12GB on my SSD. RTSS monitoring showed frame times converged from 20-80ms to 16-24ms, while AIDA64 confirmed temps at 42-46℃.