Call of Duty: Ghost's PlayStation 4 debut hasn't gone too smoothly, with some reviews citing noticeable performance issues - even compared to the 360 game - along with the recent revelation that the single-player campaign is only running at 720p and not the full HD 1080p resolution promised by the developer.
Curiously, it turns out that the resolution issue is just a bug that slipped passed quality assurance testing, and this has since been resolved in a day-one patch. All retail and download copies of Call of Duty: Ghosts are affected, so in order to get the full 1080p experience you'll need to download and install the update when it goes live in time for the PS4's European release on the 29th November.
So, the PS4 version of Ghosts now runs natively in 1080p across all modes, but how much of an upgrade are we looking at? And have the performance issues pointed out by early reviews been resolved? While working on the upcoming next-generation Face-Off, we took the time to find out, capturing a few hours of the game with and without the patch installed to get a comprehensive view of the situation. Our head-to-head video below should give you an idea of what to expect, and we've also put together a small comparison gallery.
First up, it's clear that the patch restores 1080p resolution, as promised. Imagery is naturally much sharper, and the increase in artwork clarity is obvious. While the compromised 720p presentation is clearly superior to the current-generation versions of the game, the boost in resolution to 1080p makes the difference far more obvious.
Now equalised with the PC version at native 1080p, we also get a sense of just what compromises have been made in the PS4 game compared to the flagship computer version. Initial impressions reveal a downgrade in texture resolution, slightly lower quality shadows, and less advanced ambient occlusion offering less coverage across the scene.
"1080p resolution is restored to the campaign, giving us a kind of halfway house between the launch version and the PC running at max settings."
The improved lighting model over the consoles remains, however, as does the addition of expanded visual effects work. Interestingly, the PS4 game isn't quite as sharp as the PC release despite now rendering at the same resolution: it turns out that post-process anti-aliasing - perhaps FXAA - is used on the PS4, slightly smoothing over texture detail in comparison to the sharper approach provided by multi-sampling on the PC.
We'll be taking a closer look at things in the Face-Off, but for now there's certainly a noticeable difference between the PS4 and PC versions of Ghosts, even if the two share many of the same graphical upgrades over the current-generation console releases.
One of the main issues surrounding the PS4 version of Call of Duty: Ghosts is the somewhat erratic frame-rate reported by reviewers. On playing the unpatched version of the PS4 code for the first time, the difference in smoothness between the mostly solid 60fps of the 360 game and the more inconsistent PS4 release is quite obvious - in many scenes we see the appearance of judder and what appears to be slowdown on the PS4, perhaps surprisingly in areas where performance isn't impacted upon in either the PS3 or 360 versions.
Taking the affected clips and running them through our performance analysis tools, we expected the results to show clear frame-rate drops and small bouts of tearing, but surprisingly this wasn't the case at all, with the results showing us a largely locked 60fps bar one or two minor dips and a solitary torn frame. Furthermore, when seeking through the footage in performance-affected areas we were confronted with unique frames on a consistent basis, thus indicating a 60fps update that we just didn't feel when playing the game.
So just what is going on? Well, a close look at our captures reveals that Call of Duty: Ghosts actually runs at higher frame-rates than 60fps on a fairly frequent basis, despite the video output being limited to 60Hz. In scenes where we experienced judder and perceived frame-rate loss, what we are actually seeing is the appearance of skipped and incomplete frames - an effect that is arguably far more noticeable than a few prolonged drops down to 50fps or so seen the 360 version of the game.
Since the patch restores the correct 1080p rendering mode, you would assume that these performance issues caused by the game running fasted than 60fps would be resolved, if not heavily reduced due to the additional per-pixel workload undertaken by the GPU - there's simply far less opportunity for the engine to be able to render frames faster than the targeted refresh rate. The good news is that the issue of skipped frames is reduced to a noticeable degree, particularly in some of the opening moments of the game, although the problem hasn't been completely eliminated. There is still noticeable judder present throughout the patched campaign that appear on a regular basis, which is often distracting when trying to line up a quick succession of precise shots in the heat of battle. Update: Having reviewed the patch captures, there's an odd issue with tearing which caused some confusion, but we're fairly convinced now that in the revised version of the game at least, any judder is down to frame-rate drops and not the game running faster than 60Hz.
"Stutter in the launch version wasn't down to dropped frames - but rather the game running faster than 60fps. This is improved with the 1080p patch, but the increased res introduces frame-rate drops."
The increase in pixel workload also means that the engine drops frames more often in demanding scenes. At worst we're looking at a drop down to 40fps when the engine is more heavily stressed, while most of the time the dips in performance stick to fluctuating between 50 and 60fps. Thankfully, the effects of these normal frame-rate drops are less obviously visible than the judder caused by the renderer exceeding the 60Hz refresh, although even with the 1080p patch enabled things don't appear as smooth as the Xbox 360 version of the game.
So, on the whole, while the issues with stuttering are not completely gone, we'd highly recommend downloading the day-one patch before you start playing Call of Duty: Ghosts on PS4. Extra frame-rate drops and the inclusion of small pockets of traditional tearing are apparent compared to the unpatched, upscaled 720p, but the experience is also more consistent, if not quite as stable in demanding scenes.
The boost to a full 1080p resolution is also worthwhile: images are sharper, clearer, and better defined, while the slight texture blur caused by the use of FXAA has less of an impact on overall image quality due to the additional pixel precision afforded by the higher resolution framebuffer.
Overall, though, the patch is far from perfect, but it is a significant improvement over the initial 720p experience.
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