Since its public debut in February, Sony has made a lot of hay out of the 8GB of high-speed GDDR5 RAM that will be available in a unified architecture on the PlayStation 4. But a new report suggests that game developers will generally only have access to 4.5GB of that RAM, with the rest taken up by the underlying OS.

The folks over at Digital Foundry cite "current PlayStation 4 documentation shown to Digital Foundry by a well-placed development source" in detailing the RAM breakdown. The numbers aren't set in stone, though. Digital Foundry reports that developers can take back as much as 1GB of "flexible memory" from the OS when it's available. However, taking back this memory isn't as simple as flipping a switch; it's complicated enough that only first-party games may be able to do it at first, according to the report.

For some context, the Xbox One devotes a comparable 3GB of its 8GB of RAM to the system software, according to reports, and the Wii U uses a full half of its 2GB of RAM for the OS. On PCs, Windows 8 needs 1GB of RAM, while OS X Mountain Lion requires 2GB of memory, according to official specs.

The PS3 reportedly uses 96MB of its 512MB of RAM for the OS, while the Xbox 360 uses 32MB of its 512MB—much smaller proportions than their successors. Both the Xbox One and PS4 are offloading more functions than usual to the underlying OS this time around, though. Microsoft and Sony are touting the ability for their new systems to switch rapidly between games and other apps on the system, a feature that likely eats up a lot of RAM overhead. The console makers are also talking about features like Microsoft's SmartMatch and Sony's expanded social features that constantly run in the background.

Still, reserving anywhere from 35 to 45 percent of the new systems' RAM for nongaming OS functions seems a bit extreme. Game developers are definitely going to want access to those system resources before long, especially when it seems that early PS4 demos are already using 4.6GB of RAM, including 3GB reserved exclusively for graphics.

In Sony's case, at least, there's some hope that this allocation could change in the future, with "sources close to Sony" suggesting the OS could take up less RAM with future streamlining updates. On the Xbox One, on the other hand, Microsoft has reportedly carved out 3GB as a strict, inflexible OS allocation "in order to allow the background platform to evolve over a ten-year life-cycle." In other words, Microsoft is basically saying, "Sorry, Xbox One game developers. You can't use that RAM because we might need it for something later."

In any case, we should probably get used to having more and more game console hardware devoted to background functions that aren't directly related to running games. After all, it's an "all-in-one entertainment set-top box" world, and gamers are just living in it.