There is no known VRAM usage leak in GTA V.
There is no known VRAM usage leak in GTA V.
There seems to be a stability issue with your GTX 660SC. At first it runs smoothly but slows down near memory limits, causing poor performance. This reminds me of a past problem where relocating components and mixing SATA cables led to data corruption. Even after resetting the OS and reinstalling GTA V, the issue persists.