The good folks over at VG247 have compiled a selection of rumours and anonymous information about the upcoming next generation consoles from Microsoft and Sony.
According to the report Microsoft are having some issue with chip manufacturing for their new console and production has been pushed back. It should also be noted that insiders now refer to the console as Kryptos and not it's previous working title Durango. As usual working titles seldom remain for the commercial release.
The processor, called Oban has been developed by AMD, and they will also supply Sony with the centrepiece of their next console - a chip called Thebes. Production on Thebes is apparently set to commence well after Oban and this puts Playstation 4 in line for a release either in spring 2014 or fall 2014.
As always these rumours are just that at this point - rumours.