The PlayStation 4 will reserve 3.5GB of its RAM for the operating system, a report on Eurogamer's Digital Foundry has said.  
Sony's next-gen console comes with 8GB of GDDR5 memory, leaving 4.5GB of RAM guaranteed to developers of PlayStation 4 titles.  
However, sources speaking to Digital Foundry said an additional GB of  RAM can be used as flexible memory--giving developers up to 5.5GB of  total RAM--but only if the PlayStation 4 operating system can still  function without the extra memory.  
Additional sources add that this 3.5GB requirement could be reduced once  the work on the PlayStation 4 OS is complete and potentially  streamlined.  
Much of the allocated RAM for the OS will allow for some of the  PlayStation 4's new system features, like application switching, and  being able to pause and resume games. 
