http://www.eurogamer.net/articles/digitalfoundry-resolutiongate-the-fallout
While Digital Foundry has yet to see either next-gen version of Call of Duty, our experience with Battlefield 4 demonstrates that you can easily see the visual difference between them. The Xbox One version holds up well given the gulf in resolution, but it doesn't require a pixel counter to tell that the PS4 game is crisper and cleaner either. At last week's Battlefield 4 review event in Stockholm, we noted that the resolution change from one version to the next was obvious to many of the press in attendance, with some even suggesting on-site that the PS4 version was operating at native 1080p when its actual resolution was 1600x900.
The reality for Microsoft is that the raw spec differential it has battled against is not only borne out in what is arguably the most technologically advanced multi-platform game of the next-gen launch, but the gulf actually increases on a title that, on the face of it, isn't pushing boundaries to anything like the same degree.
However, the hardware make-up itself could be more troublesome for multi-platform developers in the longer term, despite Microsoft's outline of how the Xbox One tech operates and the theoretical advantages it chose to highlight. In our In Theory piece, we could only address the teraflop difference - we couldn't measure the impact of Xbox One's reduction in memory bandwidth, and we certainly couldn't factor in what was then the big unknown: the controversial 32MB of Embedded Static RAM (ESRAM) built into the Xbox One's central processor.