Blue's News has posted the system requirements for GTA V at 4K. The verdict? If you want 60fps at 4K you are going to need a "high end SLI or Crossfire setup."
"To run the game on a 4K display at 30fps," says Hoare, "youll need at minimum an AMD HD 7870 or Nvidia GTX 760 with 2GB of VRAM." As for the 4K at 60 frames-per-second, that'll require a "high-end SLI or Crossfire setup."