Rockstar has warned players not to install the second disc included with the Xbox 360 version of Grand Theft Auto 5. In a tweet posted last night, Rockstar said that it does "not recommend" installing the Play disc, in order to ensure "optimal performance". Installation of the first disc is mandatory and takes around 8GB of HDD space. The PlayStation 3 version also requires a mandatory install, again at around 8GB. It isn't yet known why installing the second disc may lead to problems, but it's likely related to an issue with data streaming from the HDD. Halo 3 famously faced performance problems after being installed, having been optimised to run directly off the disc.