According to a report from the hardware sleuths at Digital Foundry, PS4 has reserved almost half of the PS4’s RAM for it’s operating system. Sony’s documents reveal that 3.5 GB of RAM space is dedicated to functions of the OS, leaving as much as 4.5 GB exclusively for video games.
Sources say, “It may be possible for developers to requisition up to one additional gig of space, provided the operating system can spare it at the time. This may also be a luxury most easily used by first-party developers during the early life of the console.”
This brings the PlayStation 4’s memory allotment similar to that of the Xbox One, which is 3 GB. Both of them ship with 8 GB in total.