The system requirements for GTA 5 are unknown because it has not been announced whether or not the game will be released for the PC. So in other words the only “system requirements” for GTA 5 are either an Xbox 360, or a PlayStation 3.
Currently the only systems that GTA 5 will be released for are the PS3 and Xbox 360. Because of this we don’t really know the system requirements. Rockstar games does not have a good history with PC releases so the chances of a PC release aren’t particularly high. This doesn’t necessarily mean that the game will not be released for PC sometime in the future, but it certainly won’t be released at the same time as the Xbox 360 or PS3.
Be ready for the release of GTA 5, it’s coming up soon, and is to be the biggest release of the entire fall of 2013.
Check out the "suggested by the author" links below for more GTA 5 information.