Update 2/3/14 17:45 GMT: On closer inspection, we see parallax occlusion mapping used sparingly on PS4 and PC in the The City hub area, which adds texture extrusions over the Xbox One release. For a majority of surfaces this effect is avoided entirely across all platforms, and for others it's subtle. The most notable contrast is to the centre road brick-work of Stonemarket, though texture quality is identical for any surfaces surrounding it. It's a curious point in favour of the PS4 version in a comparison that is already close - though as documented, its blurrier texture filtering is a trade-off that is worth considering. This is also a separate issue to tessellation - which is engaged on all platforms. We can also confirm both versions are fully installed before starting this test, as with all Face-Offs where the option is available. We hope this clears up any confusion.
Update: Criticism has arisen on some of the arguments Digital Foundry made. Judge for yourself, you're all old enough (I hope).
The deal is DF are lying. It's as simple as that at this point. I'm not digging back through the thread so here's just two points of note:
Pop in on X1 too but appears worse:
They say the X1 has POM but it clearly doesn't:
Now add in better resolution and better framerates. Which version is the clear winner here?
In the spirit of openness among developers as of late, the studio has already declared in advance that the game is running at a full 1920x1080 on PS4, while the Microsoft next-gen release runs at 1600x900 - a state of affairs confirmed by our own pixel count. However, due to the use of high quality FXAA post-processing on both platforms, the dropped pixel tally isn't a major point of differentiation. Bird cages shimmer, while hair and fur shaders show up aliasing artefacts to a more notable degree on Xbox One in motion - but they are also an issue on PS4 and PC too. But for the rest of Garrett's clambering across The City, Thief's base image is neatly presented regardless of platform.
Sony's platform does run at a disadvantage in another regard though. Unlike the other versions, the PS4 uses trilinear filtering to treat floor and wall textures, creating a blur across far-away surfaces. It's a difference that sticks out when using the PC version's 16x anisotropic filtering, which itself is like-for-like with the clarity of the Xbox One release. Trilinear filtering is a cost-saving trick that suits games running at lower resolutions, where the tail-off in texture sharpness isn't so visible at a distance. For a game running at full 1080p though, Thief is doing itself a disservice here, and there's little to demonstrate why Sony's console can't compete with Microsoft's platform here.
Each version is guilty of genuine frame-rate drops too, especially when traversing main roads in The City. This manifests more aggressively on Microsoft's platform, where drops down to 20fps are possible, as compared to 25fps on PS4 - but in amongst the frame-pacing issues this is trivial. The stimulus seems to be interactions with multiple guards, and travelling at high speeds around the game world - neither of which are necessarily the core tenets of a stealth game. In either case, the PS4 version technically holds steadier at these particular stress points, but the end result still appears choppy.
In terms of PC-side performance, there's nothing to worry about where any gameplay is concerned. As expected for a game based on Unreal Engine 3, its scalability across a range of hardware is dependable, and hitting 1080p at 60fps with all settings maxed out proves no issue. Our test rig, equipped with an Intel i7-3770K clocked at 4.3GHz, 16GB of RAM and a GTX 780 Ti manages to hit this target easily enough - the only strain coming from the game's benchmark test, which drops us down to 50fps as we pass through heavily fortified city gates.
If you've just bought a next-gen console, this Thief reboot is likely not your best choice for showing off its strengths. Visually, the PS4 should be the front-runner given its 1080p presentation, but through the virtues of effective anti-aliasing, the 900p frame-buffer used on Xbox One holds its own in practice. However, the PS4's weaker texture filtering does factor into the comparison more visibly, with assets appearing blurrier than they should at a distance, and asset pop-in proving slightly more evident. Given that all other settings are a match between next-gen platforms, the Xbox One release - surprisingly - stacks up favourable against a maxed-out PC playthrough.
Performance on PS4 and Xbox One counts as a bigger concern, and neither deserves any sort of recommendation here. Frankly, it feels unpleasant to control Garrett when moving with any haste - not due to frame-rate dips alone, but because of the pacing of these frames, leading to stuttering. We'd encourage buying the well-optimised PC version, as handled by port veterans Nixxes, over either of these next-gen releases as there are far fewer issues in this regard.
More at Digital Foundry, including comparison pictures & video
All in all, it's hard not to be disappointed on a technical level with Thief. It's often our refrain, but in this case we'd strongly urge opting for the PC release if it's an option. If you're committed to buying for one next-gen platform or another, the superior texture filtering on Xbox One means it carries itself slightly better in the visual stakes - but frame-pacing aside, for the most part all three versions match up very closely indeed.