Sony has put to rest the speculation on PS4’s RAM. Reports have suggested flexible memory is 512MB and developers are guaranteed 4.5GB for development.
•”Direct Memory” is memory allocated under the traditional video game model, so the game controls all aspects of its allocation
•”Flexible Memory” is memory managed by the PS4 OS on the game’s behalf, and allows games to use some very nice FreeBSD virtual memory functionality. However this memory is 100 per cent the game’s memory, and is never used by the OS, and as it is the game’s memory it should be easy for every developer to use it.