The fine folks at Digital Foundry are reporting an interesting rumor about the PlayStation 4’s RAM allocation. According to a document produced by a development source, the PS4 will provide 4.5GB of baseline guaranteed memory for games and can request an additional 1GB of flexible RAM if needed.
While its not clear how this “flexible memory” will work, it does sound like games that will make use of additional RAM may have the OS free it up dynamically offering 5.5GB of GDDR5 RAM to game development as needed.
Earlier Sony leaked documents revealed contradictory information to this rumor as it stated that only 512MB of RAM would be reserved for the OS. This may have been true at the time when the PS4 was slated to only have 4GB of GDDR5 RAM before Sony decided to bump this up to 8GB.
DF believes that Sony may be conservatively reserving memory ahead of time for ambitious plans for the PS4’s operating system or at the least, keep that option open. In essence, Sony may be preemptively walling off 2.5GB of RAM for the OS as most first gen launch titles such as Killzone: Shadow Fall won’t need additional RAM as they were developed with a 5GB GDDR5 RAM total memory pool in mind before Sony bumped this up to 8GB.
This approach smartly allows Sony to take advantage of that 2.5GB pool down the road if needed for the OS, or if game development becomes resource intense in a few years, additional memory could be freed up without impacting launch titles while dynamically providing more resources to future titles.
DF’s source at Microsoft reveals that the Xbox One’s 3GB RAM reserved for the OS is “set in stone,” and most likely would not change in the future. This is in part due to Xbox One’s three distinct operating systems built into the console to support TV overlaying, Windows 8 kernel and an orchestration layer for “snapping.”
As DF points out, Sony has a history of continuously working to reduce the OS footprint as seen on the PS3. Later on in the PS3’s life, Sony reduced its OS footprint by more than 50 percent from 150MB to 50MB when it freed up 70MB of memory.
A source close to Sony revealed that the decision to wall off 2.5GB of RAM on the PS4 initially was made “leaving the door open” to free up more memory as needed down the road.
The PlayStation 4 boasts a GPU that is 40 to 50 percent more powerful than what’s found in the Xbox One and also utilizes high-end GDDR5 RAM found in graphics cards, while the Xbox uses DDR3 general workstation memory. The PS4 is slated to launch later this year priced at $399, with the Xbox One priced at $499.