When Sony revealed the PlayStation 5 Pro, it did so in a really completely different method to the reveal of PlayStation 4 Pro and PlayStation 5. While lead system architect Mark Cerny was ‘grasp of ceremonies’ for the Pro reveal, the debut has a shortlived nine-minute affair – and proportion of that run-time celebrated the achievements of the usual PlayStation 5 console. It was a far cry from the detailed presentation given for the reveal of Sony’s first ‘Pro’ console and considerably bereft of element in comparison with the now legendary ‘Road to PS5’ presentation given by Cerny in March 2020. We had been left hungry for extra particulars – and now, they’ve lastly arrived.
A great three months after the reveal, Sony has delivered a model new deep-dive presentation into the {hardware} design and certainly the imaginative and prescient behind PlayStation 5 Pro – and it is necessary stuff. The philosophy behind the console marks a sea-change in the way in which that consoles can be made. While the core graphics rendering tech of the PlayStation 5 Pro has been enhanced over the usual machine, Cerny sees a future the place machine studying performs a key function in console design, and whereas rasterisation is nearing its limits, he sees huge scaling in ray tracing capabilities going ahead.
It’s a imaginative and prescient that shares commonalities with Nvidia’s technique during the last six years, besides the impression we get is that AMD will proceed to be Sony’s associate of alternative in delivering this new imaginative and prescient. To that finish, a brand new ‘Amethyst’ collaboration between Sony and AMD has been introduced.
Digital Foundry’s Oliver Mackenzie had the prospect to see the brand new Cerny presentation a number of weeks in the past and to interview Mark Cerny himself, alongside Mike Fitzgerald – Insomniac’s director of core expertise. However, the presentation itself is one thing that every one Digital Foundry group members had been keen to debate, so this is our response to the speak – and, after all, an outline of the whole lot we have discovered.
GPU overview: RDNA 2.x, 16.7TF
The most blatant evolution from the bottom PS5 to the PS5 Pro comes when it comes to its graphics processing horsepower. Rather than growing CPU efficiency, bettering storage speeds or focusing on larger decision shows, as you would possibly anticipate from a model new console, the principle focus with PS5 Pro is shoring up efficiency and picture high quality with a extra succesful GPU. Interestingly, the PS5 Pro GPU remains to be based mostly on AMD’s RDNA 2 (RX 6000-series) structure, however with some options backported from RDNA 3 (RX 7000-series) – and from RDNA 4 (RX 8000-series, anticipated 2025) as effectively.
At a typical clock velocity of two.17GHz, the PS5 Pro is able to a 16.7TF of efficiency – half the 33.5TF erroneously quoted earlier than launch. This is extra instantly corresponding to the circa 10TF quantity connected to the bottom PS5, versus the inflated (or “flop-flated”, as Mark Cerny places it) RDNA 3 teraflop counts. Other specs line up with early PS5 Pro leaks, together with 30 WGPs, 60 compute items and a max increase of two.35GHz – although this frequency is not prone to be seen beneath regular working situations, maybe resulting from energy constraints. The most clock velocity of the usual PS5 is 2.23GHz, however the presentation means that typical working velocity is identical 2.17GHz as PS5 Pro so typical TFLOPs is circa 10TF, not often hitting the ten.23TF quoted within the authentic specs. As this technology has confirmed, nevertheless, TFLOPs is proving to be an more and more meaningless metric – a state of affairs acknowledged by Mark Cerny within the new presentation.
As for why PlayStation 5 Pro is not totally embracing later AMD graphics architectures, the reason being very easy: shader code for the PS5 GPU wouldn’t perform on later AMD {hardware}, and there is no means by which these shaders could possibly be re-compiled in present video games. Shader compilation on the fly? It’s not viable for PS5 and – belief us – you would not need it both. Therefore, PS5 Pro has to make use of the identical RDNA 2.x baseline, with extensions added for brand new options – akin to enhanced ray tracing.
In phrases of different options, we additionally know from separate disclosures to builders that the PS5 Pro has the total RDNA 2 characteristic set, together with mesh shaders and {hardware} VRS, and there is an additional 2GB of (slower) DDR5 reminiscence on board. Of that, there’s over one gigabyte of additional reminiscence out there to builders. The GDDR6 reminiscence used right here can be round 28 % quicker than on the bottom PS5 – 576GB/s versus 448GB/s – regardless of being related on an identical 256-bit bus.
Ray tracing enhancements
Part of the PS5 Pro’s attraction is its important enchancment when it comes to RT efficiency, permitting builders to make use of these options extra liberally in PS5 Pro-enhanced titles with out sacrificing picture high quality or frame-rates to the identical extent as on the bottom PS5. This is achieved via the RDNA 2.x structure of the bottom PS5, with new extensions added from later RDNA expertise.
The PS5 repurposes the feel mapping items to do field and triangle intersection exams for ray tracing, with the PS5 Pro rushing up this a part of the method by two or thrice. The Pro additionally helps BVH8 fairly than BVH4, which additionally gives a speed-up. PS5 Pro additionally provides stack administration in {hardware}, which once more helps the traversal stage in ray tracing and was beforehand solely seen in Intel and Nvidia {hardware}, not AMD.
Finally, extra divergent RT sees a higher efficiency increase than extra coherent RT on PS5 Pro. This divergent/coherent spectrum basically describes the complexity of RT calculations, with shadows and reflections on flat surfaces being extra coherent, and reflections on curved or bumpy surfaces being extra divergent. Again, Nvidia and Intel have give you good methods to deal with extra divergent RT, akin to {hardware} sorting items and shader execution reordering, and although we do not see actual replicas of these concepts right here, the traversal upgrades and transfer to BVH8 must imply the PS5 Pro is significantly better outfitted in its predecessor to sort out these extra computationally costly RT calculations. That opens the door to builders extra simply utilizing a wider vary of fabric roughness for reflections, for instance, fairly than solely sticking to mirror-like or near-mirror-like reflections.
Mark Cerny postulates that there’s a restrict to how far we are able to take rasterisation. One avenue to exceed these limitations is thru RT, which has a whole lot of potential to scale with extra analysis. Seeing these enhancements from Sony means that RDNA 4 is pushing extra in that course, which is thrilling stuff.
Of course, we nonetheless do not know for certain how RDNA 4’s RT efficiency will end up – it seems to be like a big step ahead, however there’s nonetheless no equal to the RT core featured in Nvidia’s RTX 20-series structure onwards, which permits for extra concurrent workloads. AMD has mentioned in shows the way it’s utilizing higher quantities of cache on its PC GPUs to suit extra into the BVH, so it’s going to be fascinating to see how the desktop RDNA 4 chips carry out with that extra enchancment.
Machine studying and PSSR
As effectively because the PS5 Pro’s baseline RDNA 2.x being upgraded with what Sony calls “future RDNA” for ray tracing, it additionally comes with “customized RDNA” for machine studying, particularly PSSR upscaling. Rather than utilizing an present upscaler, Mark Cerny informed us that Sony targeted on velocity and minimising the period of time per body that their upscaler required. They had a alternative between NPU and GPU {hardware} for this, and ended up going with the GPU.
The precise implementation is sort of fascinating, as Sony found that even processing a single layer of a 4K 16-channel picture at 128MB was restricted by reminiscence bandwidth whereas utilizing solely three % of the circa 300 TOPS out there. The naïve resolution was to take a smaller portion of the picture via the chip without delay, however then you find yourself with issues the place the perimeters lack crucial details about the encompassing tiles, in order that information must be discarded.
In the tip, Sony opted to mix their vector registers within the WGPs, giving them a complete of 15MB of reminiscence and 200TB/s of reminiscence bandwidth. It’s an identical strategy to how AMD dealt with RT, the place you are still utilizing generalised {hardware} to perform a particular objective. The repurposing is probably going area-efficient when it comes to the general silicon footprint, does not require huge modifications to RDNA, and appears to have allowed Sony to achieve its velocity objectives for PSSR.
However, PSSR is not but a “fully-fused” convolutional neural community (CNN), one thing that Intel notably achieved with their first launch of XeSS. Being fully-fused imparts a velocity benefit, as you are not touching system reminiscence partway via upscaling a single body. Based on DLSS taking lower than 1ms and PSSR taking round 2ms via our tough calculations, it signifies that there’s the potential for video games to run quicker if that is achieved sooner or later. It might additionally open the door to upscaling getting used at larger frame-rates (eg 120fps) the place a circa 2ms upscale runtime is a big proportion of the 8.3ms out there for a complete body to be rendered. There is the chance that AMD might take an identical strategy with RDNA 4, making modifications to the principle CUs to make it potential to run convergent neural networks domestically on the GPU.
The future: Amethyst, ML exploration and next-gen
Sony has additionally introduced a collaboration with AMD referred to as Amethyst – itself a repurposed AMD GPU codename from 2014, with its purple color coming from the mix of Sony (the Blue group) and AMD (the Red group). The thought is to make {hardware} architectures that work effectively for light-weight CNNs helpful for real-time sport graphics, in addition to high-quality CNNs for sport graphics. There’ll even be collaboration on the community architectures of these CNNs. Both events will be capable of entry all of those architectures for his or her merchandise.
It seems like AMD is main the way in which on the principle GPU designs however Sony and AMD have this machine studying collaboration that ought to hopefully push issues ahead for each firms when it comes to machine studying and ray tracing. Sony will get the advantage of iterating upon PSSR on a bigger scale, AMD will get to minimise the R&D hole between itself and Nvidia. It’s not clear whether or not there can be some cross-pollination between PSSR and FSR on RDNA 4 GPUs, and it will be fascinating to see the place Microsoft’s upscaling efforts additionally fall on condition that additionally they have a PC focus, but compete towards PlayStation with the Xbox.
This is not nearly upscaling both, it is about pc graphics normally. There’s loads of machine studying potential that Mark Cerny appeared fairly excited by in our dialog, together with denoising, bettering texture high quality and texture streaming, possibly even geometric high quality, all inside the restricted bandwidth and reminiscence house out there on consoles. That’s the type of factor that Sony ought to be evaluating for PS6 and an endeavour like Amethyst ensures that reaching a few of that is doable on that sort of a time frame. Likewise, saying a partnership of this nature means that Sony is sticking with AMD for his or her next-gen console, as its main advantages will not be out there within the subsequent couple of years.
As effectively because the PlayStation 6, there are many thrilling prospects for the PS5 Pro as builders become familiar with the brand new consoles capabilities. There’s definitely potential for extra superior RT implementations in addition to improved iterations of PSSR that accomplish extra uniformly good outcomes. There’s additionally the chance for extra enhancements to working video games beneath back-compat if Sony needs to make use of ML to boost the present library of video games.
Overall, it has been fascinating to be taught extra in regards to the PS5 Pro, and we encourage you to learn our interview with Mark Cerny and Mike Fitzgerald for extra element on the PS5 Pro, its growth and potential for future enchancment.
