another EuroGamer article. sounds so good!!!:
"In designing for compatibility, there are two choices that we can take from a performance perspective," Microsoft's Andrew Goossen, Technical Fellow, Graphics tells us. "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."
What Goossen described as the 'emulation' approach is seen in PS4 Pro's design. Sony's latest console uses a 'butterfly' approach to GPU design, effectively mirroring the base unit's GPU with an extra rank of 18 compute units, doubling power (more so once extra frequency is added). With this approach, Sony can ensure complete compatibility simply by turning off the additional, new 'half' of the graphics core. It's an elegant solution, but what's clear is that the newly introduced boost mode doesn't deliver the Pro's full power to existing base PS4 titles.
Microsoft has taken the harder route - and it has done so by necessity. It doesn't have the option of doubling up on its existing design, as Scorpio is a radical architectural overhaul. Here, it's down to the platform holder to take ownership of compatibility issues, but the advantage is this: unlike PS4's boost mode, Scorpio theoretically allows for the full power of the new console to be deployed on older games. In fact, there are five different ways in which Scorpio aims to improve the experience for owners of existing Xbox One games - and these should also apply to Xbox 360 back-compat titles.
1. Smoother performance and no screen-tearing
"We bring to bear all 40 compute units and the full 1172MHz clock-speed [of the Scorpio GPU], we're bringing those to bear on all the games possible," says Andrew Goossen. "Now, I have a caveat a bit later about all the compatibility testing we do for these and
some of the implications, but we can bring all the 40CUs, all 1172MHz, of course the full 2.3GHz on the CPU."
2. Maximum possible resolution on dynamic titles
A popular technique in games development is to adapt dynamic resolution scaling. The idea here is straightforward: when a game is in danger of losing its lock on its performance target, be it 30fps or 60fps, the title scales down the image, running it at a lower resolution in order to maintain a smoother frame-rate. There are many games out there that support dynamic scaling - Doom 2016, Halo 5, Gears of War 4, Battlefield 1, Call of Duty: Infinite Warfare and The Division, for example.
"With the additional performance of the Scorpio Engine, we expect to see those titles hit the maximum render resolution that those titles support," says Goossen. "As you know, we can't boost it to 4K, but definitely the maximum resolution the game supports, we should be able to run it."
We're looking forward to testing one particular title: CD Projekt RED's The Witcher 3. The developer states it supports dynamic resolution scaling, but we've yet to see it break the 900p barrier. Given Scorpio's 4.6x improvement in performance, surely if the tech is in there, we should hit native 1080p - and iron out the performance wobbles at the same time.
3. Improved texture filtering
Resolution is an important, defining aspect of image quality but it is not the only one. Texture filtering is hugely important - and it's actually an element where both PS4 and Xbox One have let us down a little compared to the same titles running on PC, where the full force of 16x anisotropic filtering can make a big difference.
"We built into the hardware the capability of overwriting all bilinear and all trilinear fetches to be anisotropic," Andrew Goossen reveals. "And then we've dialled up the anisotropic all the way up to max. All of our titles by default when you're running on Scorpio, they'll be full anisotropic."
Good quality texture filtering will make a big difference to a large number of Xbox One titles, where typically 4x anisotropic tends to be the balancing point chosen by developers. The leap to 16x, enforced at a system level by the back-compat engine, is a huge boon, especially in concert with the complete lack of screen-tear and smoother overall performance. More good news: this new feature extends to Xbox 360 games too.
4. Scorpio GameDVR support
Microsoft's plans for GameDVR on Scorpio are impressive - the hardware team is leveraging the new console's next-gen media block to provide 4K60 video capture with no performance hit, utilising the highly efficient HEVC codec for pristine visual quality. GameDVR works for back-compat titles too, which has some key benefits.
"Even though a lot of this content will be 1080p, we'll have the benefit of HEVC, the ultra high bit-rate, so we'll be able to do those retroactive screen captures at a really high quality."
5. Faster loading
In a world where a Battlefield 1 campaign level can take anything up to two minutes to load, this one is especially welcome. "We're able to say that game loads will be fundamentally faster," Goossen reveals. "There are three ways we say that - one of which is the CPU boost. The 31 per cent CPU boost in terms of clock will help games that are CPU-bound in terms of their IO."
Assets streamed from a hard drive often arrive in a compressed state, requiring the CPU to decompress them. Extra frequency on the CPU cores can make a difference here - sometimes a dramatic one. Case in point: the Division on PC can actually max out all six cores and 12 threads on an overclocked Intel Core i7 3930K, just through loading content.
"The second one is that we've that we've improved the hard disk speed," Goossen adds. "We're actually promising developers a 50 per cent improvement in overall bandwidth for the purposes of driving 4K textures, but this also helps us in this situation where you're running existing Xbox One and Xbox 360 titles. They will also benefit from the faster hard disk."
This is an example of how another spec boost in the Scorpio arsenal means good things for other areas in the system - a factor that also comes into play on the third and final way in which Scorpio will improve back-compat loading times. The new console gives developers eight gigs of RAM to play with, but existing Xbox One titles were only built to utilise 5GB - something the hardware team use to their advantage.
"If Xbox One games take five gigs, we have three gigs left over. We do a file system cache on that. Any repeated IOs... if you go into a race and come out or if you go into a fight and come out, we've got a nice boost right there for load times as well."