Grand Theft Auto V is officially released tomorrow, and Rockstar Games is warning Xbox 360 owners to not install the second disc – the play disc – onto their consoles. GTA 5 will ship on two discs for the Xbox 360 and the first disc is an 8 GB install, while the second disc should remain in the DVD player to be played or can be installed onto a USB drive.
The reason being is that GTA 5 is so large that Rockstar Games designed the title to split the data over the two discs. Since the game is engineered to load as quickly as possible, the optimal solution is to install one disc of content onto the hard drive, while the DVD drive accesses the second disc of content. This way, the Xbox 360 is able to load data from both discs at the same time. Naturally if you install the second disc onto your Xbox 360’s hard drive, that means the game is trying to load two discs worth of content off one source. This is also the reason why you can install the second disc to an external USB drive and have no issues, because the system will load from two sources.
Source: Twitter