Texture glitches.

The only solution I found was to uninstall the x64 version and install the x85 (32-bit) version, and everything started working perfectly. It's true that it doesn't recognize 4 GB of RAM, but I don't need it. 3 GB is enough for all my games. Even GTA 4 runs without any problems.

CONCLUSION: If you want to play normally with Nvidia graphics cards, install Windows Seven x86.