It's been reported that the Xbox One sports a 32 MB ESRAM under it's hood to the mainstream. This would be like a turbo boost as opposed to not having it. Be clear that, current games, so far, have not taken advantage of this in any meaningful way.
Now enter this from an industry insider: The Xbox One has dual 64 MB ESRAM's! Oh my god! That's right 128 MB ESRAM's... So now this is like super turbo with blower and superchargers, don't forget the dual exhaust.
This might just be a rumor and nothing else but with DX 12 around the corner and with MS about to announce DirectX 12 for the xbox one, well it stands to reason that there just may be some hidden guns in the X1.