But why is this happening and should it influence your decision over which of the next-gen game boxes to buy?
The confirmation comes in the form Call of Duty: Ghosts. Developer Infinity Ward says it will run at 1080p on the PS4 but only 720p on the Xbox One. For clarity, that's 1,920 by 1,080 pixels versus 1,280 by 720 pixels.
Put another way, that's two million pixels on the PS4, just one million on the Xbox One. Quite literally, the PS4 will offer double the graphical detail.
Does the difference matter?
The first question is whether this actually matters. The answer is yes, it matters. Admittedly, some people are more sensitive to graphical fidelity than others. But double the detail is a substantial difference by any metric.
That said, when there is a difference with a given game, it may not always be 720p vs 1080p. Hold that thought.
What's important to understand up front is that 1080p on an HDTV doesn't outstrip the acuity of the human eye at normal viewing distances. This is what Apple means when it talks of 'retina' displays. It means from normal viewing distances, the human eye doesn't resolve individual pixels.
But if you have decent vision, a 1080p HDTV isn't a 'retina' display. Which is why 4K displays looks miles better than 1080p displays. And in turn 720p doesn't look as sharp as 1080p.
The importance of native resolution
There's a further angle to this resolution problem. It's not just a matter of doubling the pixel count. It's the clarity of each pixel, too. The issue here involves native panel resolutions. Flat panels including LCD and OLED screens have an absolutely fixed number of pixels, unlike old school CRT screens.
That means there's just a single ideal resolution the panel can run at, only one setting at which images are shown pixel for pixel. Before the pedants drop a bomb in the comments below, pixel doubling could be argued to be an exception. But pixel doubling involves factor-of-four jumps in resolution.
Put another way, 720p to 1080p is not pixel doubling, so it's irrelevant to the PS4 vs Xbox One debate.
Anyway, most big HDTVs are now 1080p, not 720p. So not only do you lose pixels when dropping down from 1080p to 720p when gaming. You also lose clarity of individual pixels, since at 720p you have to use an algorithm to interpolate larger pixels over a non factorial number of smaller pixels. It's basically a horrible kludge that results in soft, slightly blurry images.
This applies to an extent even if you do the interpolation in the game engine and actually output 1080p to the screen. There's been talk, for instance, of the Xbox One rendering Battlefield 4 at 900p internally and then upscaling the output. But there's no way round the problems you incur when attempting to spread one pixel over one and a bit pixels. You will always lose some sharpness and clarity.
Why is this happening?
So, we now know the difference matters. The next question is why is this happening? Actually, that's easy to answer. It's because the PS4 is more powerful in graphics terms. And that means the PS4 can render higher detail graphics while maintaining smooth, playable frame rates.
Both consoles are based on very similar basic architectures, with CPU and graphics provided by chip specialist AMD. In fact, the two share pretty much identical eight-core CPUs. So we don't have to worry about that.
Where the big differences come in are graphics and memory subsystems. PS4 and Xbox One actually use identical graphics architectures, known as AMD's GCN technology. But here's the thing. The Xbox One has 768 GCN graphics cores. The PS4 has 1,152. The two consoles run at similar clockspeeds, so right from the get go, the PS4 has 50 per cent more raw shader power.
Then there's memory bandwith. The PS4 packs 8GB of GDDR5 running at 5.5GHz data rate and thus packs 176GB/s of bandwidth. The Xbox One? 8GB of DDR3 at 2.13GHz and thus just 68.33GB/s. Oh dear.
In mitigation, the Xbox does have 32MB of eSRAM offering another 102GB/s of bandwidth. But that's a misleading figure, since the eSRAM pool is very small compared to system memory. It certainly helps offset the PS4's bandwidth advantage. But an advantage it remains.
With all that in mind, there's no denying the PS4 is simply faster at rendering graphics. The end.
A sign of things to come?
So, we now know all this matters. We know why it's happening in terms of the PS4's performance advantage over the Xbox One. The final question is whether this is going to be the norm over the life of the two consoles. Because if it is, it's something you need to think carefully about before choosing which box to bag.
Here, things are much less clear. On the one hand, if you buy an Xbox One tomorrow, its hardware isn't going to get any faster over time. The PS4 will always have 50 per cent more shaders and generally be capable of rendering more detailed graphics at smooth, playable frame rates.
On the other hand, developers will get better and better at exploiting the capabilities of both platforms over time. So, the Xbox One will offer much better looking games a few years from now than it will at launch. Problem is, so will the PS4.
Since both are so very similar in hardware terms, it's hard to really see where the Xbox One is going to close the gap. Both consoles will be more efficiently exploited over time, so the performance gap will remain.
Of course, using a lower resolution isn't the only option open to developers. They can reduce shader and texture details, dumb down the shadows and lighting. But however you slice, that means lower visual quality.
Against all that, at least one unnamed gave developer has been quoted claiming that while several initial launch titles will see the PS4 running at higher resolution, they expect this practice to fall away as developers get to grips with the Xbox One.
But like we said, they'll be getting to grips with the very similar hardware in the PS4 at the same time. IGN and videogamer.com, among others, have posted a comparison videos showing Battlefield 4 running on both boxes. But such video-captured demos can be misleading, there are several steps along the way in terms of processing and compression.
And frankly, to our eyes the Xbox often looks the sharper of the two both videos and that probably says more about how each video was captured than anything else.
Game over for Xbox One, then?
Not so fast. While the PS4 will always have a performance advantage, the Xbox One is still roughly five times faster than an Xbox 360. It also has 16 times more system memory. And critically, it has as much memory as the PS4, so the scope and size of game worlds will be very much comparable.
Indeed, memory space was probably the biggest limitation for game devs as the existing consoles approached end of life, not raw performance.
The point, then, may not be whether PS4 is faster. The point may be that Xbox One is fast enough, powerful enough to do most of what game developers plan for this generation. There will be 1080p games on the Xbox One. Of that we are confident.
So what do we think overall? On balance, Xbox One games won't look quite as good as PS4 games. However the difference is not going to be complete earth shattering. It will be relatively subtle. The PS4 will look that little bit sharper.
In that sense, you probably know who you are already. If you're a sucker for super-detailed graphics, there can be only one choice. PS4. For everyone else, it's a more marginal decision. But make no mistake. Whatever advatnage PS4 has at launch, it will largely maintain for the life of both consoles.
Do the graphics differences matter to you? Let us know in the comments or tweet @TechRadar