Why does GTA V stutter in the city with Corsair Vengeance DDR5?

I was devastated when entering Los Santos; the modded cars caused massive stutters that killed my immersion. I tried increasing virtual memory to 128GB in system settings, but it was a disaster, causing 3-second freezes during scene transitions. To fix this, I used the GamePP Resource Scheduler to force five-module process priority to Realtime and killed background services. After testing, FrameView showed frame times converged to 8.2-11.5ms, AIDA64 measured memory usage at 62.4-68.7GB, and HWiNFO confirmed temps at 48-54℃.