The Online Public Beta is essentially a modified version of the standard game but with several unique additions and technical compromises:
Today, it’s hard to imagine a racing game without online leaderboards or multiplayer. But in 2004, the internet on consoles was a frontier. Gran Turismo 4 was originally slated to launch with a robust online mode. The plan? Real-time racing against six other human opponents, voice chat via USB headsets, and time trial rankings. gran turismo 4 (online public beta)