Home / Gaming / Diving into Project Scorpio’s backwards compatibility, 4K, VR, and 1080p support

Diving into Project Scorpio’s backwards compatibility, 4K, VR, and 1080p support

Now that we’ve discussed the basic technical specs of Project Scorpio, Microsoft’s follow-up to the original Xbox One, it’s time to cover some of the ancillary information, like 4K support, 1080p goodies, and VR functionality. Microsoft and Sony are pursuing different strategies with their new refreshed hardware, so it’s worth exploring what each platform offers (at least, as of this writing).

Backwards compatibility, current game improvements

All Xbox Scorpio games (that’s our shorthand, not Microsoft’s specific nomenclature) are required to be backwards-compatible with Xbox One titles. The only exception to this may be VR titles, which require peripherals that the original Xbox apparently won’t support. The general implication from Microsoft is that it takes backwards and forwards compatibility seriously, and the company’s work on Xbox 360 emulation for the Xbox One also illustrates that point.

Here’s how Andrew Goossen (Microsoft Technical Fellow, Graphics) explained the situation to Digital Foundry:

“In designing for compatibility, there are two choices that we can take from a performance perspective,” Goossen said. “One of which is to design hardware to emulate the performance capabilities of the original [console] as much as possible, or the other one is to say, we’re just going to turn on all the performance and we’re going to deal with all the issues.”

Sony represents the emulation option that Microsoft is discussing here. Boost Mode has been made available so that existing PS4 titles that aren’t optimized for the PS4 Pro can still take advantage of higher clock speeds — but not the second GPU implementation inside the console.

Microsoft is taking the harder route of making the Xbox Scorpio’s firepower available to all games, but that means checking to ensure those titles run properly and don’t suffer slowdowns or other issues.

Microsoft further clarified that while games should be able to sustain a constant frame rate on Scorpio even if they struggled to do so on the original Xbone, the new console doesn’t automatically raise the frame rate. That’s typically the developer’s decision and is tied to the game engine. (It appears developers will have the option to add support for a faster locked frame rate, but that’s up to them).

I’m not sure this is actually a problem. 30 FPS gaming gets a worse rap, in my opinion, than it actually deserves. While I still prefer 60 FPS targets, I’d much rather have a rock-solid constant 30 FPS than a game that swings erratically from 20 FPS – 60 FPS depending on what’s on-screen at any given time. It’s been my personal observation that what most people don’t like about 30 FPS is that a performance whack at 30 FPS pushes you down into stuttering territory in the 20-25 FPS range, whereas the same percentage decline from a 60 FPS target puts you in the 40 – 50 FPS range. The slower the base frame rate is, the more noticeable stuttering becomes.

Digital Foundry expects Xbox One games to run smoother, avoid screen tearing, hold their maximum possible resolutions, and offer improved texture filtering — according to Goossen, the new Scorpio system automatically converts bilinear and trilinear filters to 16x anisotropic filtering on-the-fly. In the image below, Forza Motorsport 6 Apex is using 4x AF on the left(corresponding to default texturing for the Xbox One) and 16x AF on the right.

texturefiltering

4x on the left, 16x on the right. Click to enlarge. Image by Digital Foundry

This texture filtering improvement will also carry over for Xbox 360 games played via emulation. Microsoft is also promising faster loading and improved texture decompression performance to accelerate how long it takes to actually get in-game and playing.

VR support

Microsoft expects Project Scorpio’s firepower to be primarily useful in delivering two kinds of content: VR and 4K. This does not mean that 1080p gamers are left out in the cold, but we’ll cover that separately. VR support really isn’t in question; the Polaris-class GPU inside the Xbox Scorpio is significantly more powerful than the GTX 970 or R9 290 GPUs that are typically specced as minimum hardware for 1080p VR.

Microsoft is expected to announce Oculus support for Scorpio, given that it already has a partnership with Oculus to distribute an Xbox One controller. There are also rumors of additional, Windows 10-specific optimizations that will improve VR performance in some degree, but data here is thin. We know that at least one game, Fallout 4, is being converted to VR specifically for the Xbox One. But this situation is easily the murkiest of the various Project Scorpio questions. Ars Technica points out that the next-generation Xbox doesn’t seem to have the extra HDMI port you’d expect for outputting specifically to VR, and it’s not even clear if MS will still partner with Oculus given that it is making its own push into low-cost VR headsets.

Can the Xbox One hit native 4K?

Digital Foundry’s conclusion is that some Xbox One games, if properly optimized, should be able to drive a title at native 4K as opposed to simply upscaling 1080p textures and detail settings. The one title Microsoft showed, Forza 6, was running a steady 60 FPS at 4K resolution. While that’s extremely impressive for any console, as always, we don’t recommend basing purchase decisions on the performance of a single, likely highly-optimized game.

Games that are bottlenecked by fill rate are much less likely to hit 4K resolutions, for example, because Project Scorpio’s GPU is limited to 32 ROPS. Games that put heavy pressure on memory bandwidth, on the other hand, could easily hit 4K on the Xbox Scorpio, even if they can’t maintain that resolution on a PS4 Pro — the Xbox’s 1.5x memory bandwidth advantage over Sony could be sufficient to make that happen.

Like Sony, MS has the option to use checkerboard filtering or other methods of scaling up to 4K, if they so desire. Just as with Sony, I expect there will be some games that actually hit native 4K and some that scale up to it. I’m not even sure that 4K targets are the best way to use the additional firepower — I’d prefer an upscaled 4K with better textures or possibly higher frame rates as opposed to a native 4K with a 30 FPS lock. We’ll have to wait and see how studios take advantage of the new capabilities to render a verdict on whether Microsoft’s approach works better than Sony’s. Redmond does seem fairly confident on this point; they’ve added support for 4K60p video capture with retroactive screen capture to the Xbox GameDVR app when running on Scorpio.

1080p goodies

Sony’s initial PS4 Pro messaging was almost entirely focused on 4K, to the point that you might have wondered whether the company was aware that the vast majority of TV owners (and PC gamers, for that matter) use resolutions far below that point. According to Microsoft, games rendered above 1080p resolution will be downsampled for 1080p televisions.

This is a particularly nice trait for Microsoft to offer. Downsampling and super-sampled anti-aliasing aren’t technically exactly the same thing, mostly because there are different methods to use for super-sampling (ordered grid, sparse grid, etc) and downsampling doesn’t necessarily conform to these specific approaches. At a very high level, however, here’s how this works:

Supersampling AA: Improves image quality and reduces jagged lines by taking additional subpixel color samples and renders the entire image at a higher resolution before outputting at the target resolution. The grid type chosen will impact final image quality — some grid patterns are more likely to produce blurred textures than others. If you hate jaggies, SSAA is the best way to eliminate them if your GPU can handle the much heavier workload.

Downsampling: The game is internally rendered at a higher resolution before being output at a lower resolution. This step is essentially identical between supersampling and downsampling, and in every game I’ve ever tested that offered both options, supersampling and downsampling have had practically identical performance hits and improved visual quality by the same amount.

A 1080p game downsampled from 4K still looks much better than a 1080p game rendered in 1080p — the only question is whether the GPU can keep up. The entire reason why alternate antialiasing modes like FXAA, SMAA, MSAA, CSAA, CFAA, Quincunx, TXAA  and MFAA were developed is because game devs and GPU companies have continually pushed to find new ways of improving image quality while reducing the GPU workload. Each of these methods uses a different approach to improve image quality, with results that range from “Good,” to “Better than nothing,” typically with corresponding performance hits. Downsampling is the gold standard for image quality in a situation like this, and it’s encouraging to see MS standing up for it and enabling it by default, in hardware, when playing on a 1080p TV.

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3200×1800 downsampling compared with native 1080p resolution.  check the edges of textures to see where the downsampled image smooths them compared with 1080p. Click to enlarge, image by Gamrs.co user VooDooPC.

Overall, this looks like an extremely impressive launch for Microsoft. If it comes in at the expected price ($ 499) and can actually hit 4K60 gameplay in more than a handful of titles, this next-gen console should punch well above its weight class, even when compared with PCs. Honestly, that shouldn’t be viewed as a surprise. There was a time when brand-new consoles were more than capable of matching the graphics of equivalent PCs. The Xbox One and PS4 were less-capable (but more profitable) in this regard, but Microsoft, at least, intends to play a major round of catch-up. And Microsoft appears to have learned from Sony’s mistake and is offering features that all gamers, including those with 1080p televisions, can benefit from out of the box.

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