GTA V was praised for its visuals back when it first launched on last-gen consoles. It was praised once more when it launched on current-gen consoles. Neither time was is praised as much as it was when it launched on PC, where when turned all the way up the game's visuals blew everything out of the water. Even after several large AAA releases, the PC version is still the apex of video game graphics. Let's not even get into visual enhancement mods here, alright?
However, visuals like that come at a hefty price. GTA V may be well optimized so that it runs pretty well on low-end rigs when set to medium or low settings, but venturing into the high and ultra ranges requires beastly rigs. GTA V has been used by PC gamers as a benchmarking tool, seeing just what their machine is truly capable of. In terms of scenery and objects, on ultra settings GTA V seems lifelike, with screenshots easy to mistake for photos. However, you're not going to see any of that first hand if you don't drop some solid cash on hardware. AMD rigs have particular issues with GTA V on top of that, so in terms of GPU, you'll probably have to go with the more expensive nVidia cards.
As well optimized as it is, there is always room for improvement. N8Gamez, MN8R01, Frey and decoded4620 are a team of modders hell bent on making GTA V more optimized in order to increase performance on mid-range and lower end systems. GTA V Re-Sized takes the game's texture files, and compresses them to a significantly smaller size without losing quality. Using this mod has allowed players with 1GB graphics cards to play the game with high texture and shader settings at solid FPS counts.
Did you upgrade your rig for GTA V's PC version, or have you been looking for other ways to improve performance?