We built a 'next-gen' Zen 2/Navi-based PC - how much faster is it than current-gen consoles?
Now we're playing with power.
Development kits are out, game makers are briefed. Sony's PlayStation 5 and Xbox Project Scarlett projects are under way - however, detailed specifications of the consoles are still a subject of much speculation. What has been confirmed is that both machines once again have much in common: both are produced in concert with AMD, both use the Zen 2 CPU architecture while the graphics cores are based on the latest Radeon Navi technology. The question is: can this deliver a full generational leap over PlayStation 4 and Xbox One?
I decided to get some idea of how these new technologies compare stacked up against the current-gen machines - specifically, the enhanced PS4 Pro and Xbox One X. The work was the basis of a presentation I delivered a couple of days ago at EGX 2019, where Asus Republic of Gamers helped out by building an AMD-based PC based on my specifications. Aspects of this unit were then tuned to match the increasingly compelling leaks based on the Gonzalo processor under development by AMD, a chip that is now almost certain to be the SoC within PlayStation 5.
After viewing the Gonzalo leak with some scepticism, I now believe the evidence to be fairly conclusive. A recent Gizmodo report gave PS5 the 'Prospero' codename, and although Microsoft refuted many of this leak's suggestions with regards Scarlett, my own sources have now confirmed the same Sony codename. Prospero is the lead in Shakespeare's The Tempest, and Gonzalo is a supporting character. Other leaks have also revealed Ariel as a component (the GPU, possibly) and again, this is another player in what many believe to be Shakespeare's last solo-written play. The Gonzalo leak suggests a 3.2GHz Ryzen CPU, with Sony itself confirming eight cores and 16 threads. The leak also suggests a 1.8GHz or 2.0GHz GPU clock. This is remarkably high, it has to be said. However, 7nm silicon is very expensive in the here and now - and getting more value from it would involve driving it faster.
Beyond that, there are a number of caveats to put into place before we go on. While based on the Navi architecture, we should expect Sony and Microsoft to have access to the AMD parts list from the present day into the future - in the same way that PS4 Pro delivered GPU features ahead of their debut in Radeon RX Vega. We know that both next-gen console GPUs feature hardware-accelerated ray tracing - which isn't present in the current Navi chip. Support for HDMI 2.1 and 8K video output is also effective confirmation that the display controller in the new consoles is a hardware block that's not present in the current Navi graphics chips.
I would also expect to see some extensive customisation efforts from both platform holders - both Sony and Microsoft would have seen the profound benefits of this from their efforts with PS4 Pro and Xbox One X. Also noteworthy and worth stressing heavily: we don't know how many Navi compute units are in either console, but with the Radeon RX 5700 and 5700 XT providing CU counts that match PS4 Pro and Xbox One X, we can come up with some fascinating architectural head-to-heads.
Here's the parts list for the Zen 2/Navi PC that Asus ROG put together for us:
- CPU: Ryzen 7 3700X with Wraith Prism cooler
- GPU: Asus ROG Strix RX 5700XT (RX 5700 also used)
- Motherboard: Asus ROG Strix B450F Gaming
- Memory: 2x 8GB DDR4 3600MHz
- Storage: 1TB NVMe SSD
- Power Supply: Asus ROG 650W
- Optical Drive: Pioneer 4K UHD Blu-ray
- Case: Coolermaster N300
Where we can reasonably confident about the closeness of our build is in the CPU architecture. Sony has confirmed eight cores and 16 threads, and Zen 2 is in our hands. The Ryzen 3700X is a remarkably good processor, and even at the Gonzalo leak's 3.2GHz, it effortlessly annihilates the Jaguar technology found in the current-gen consoles. Jaguar was never widely deployed on PC, but AMD did release it as a low-power, entry-level platform codenamed Kabini. I happen to own an Athlon X4 5370, the most powerful Jaguar AMD released in the PC space, and it's a genuinely awful chip judged by today's standards, and it wasn't close to being competitive when it first launched.
The console platform holders didn't have too much choice for the CPU component in the current-gen SoCs. Jaguar was the best fit as it occupied a comparatively small amount of silicon area, and didn't consume much power - a good fit for a console box. The solution to its deficiencies was to double up on core count, with two quad-core Jaguars integrated into the same SoC. Based on the benchmark here, I think it's quite astonishing just how much game makers got out of the architecture. By my reckoning, a vintage 2008 Intel Core 2 Quad Q6600 is likely as capable as the version of Jaguar within PlayStation 4. And as for comparisons with Zen 2? Well, we're in great shape for next-gen.
To illustrate, I ran a simple benchmark on both my quad-core Jaguar and Zen 2-based PCs. Cinebench R15 is far from a perfect test, but I chose it because it delivers both single thread and multi-core results and It doesn't rely much on cache or memory bandwidth (aspects our PCs that we can't match with consoles). I benched Jaguar at 1.6GHz to match PS4, and the 2.3GHz clock of Xbox One X, effectively giving us the lowest and highest extremes of the architecture's use in the consoles. As it's a quad-core part and the consoles have eight cores, I doubled up the result to give an (optimistic) insight into how two of them may work together. Zen 2 wouldn't run at 1.6GHz, but 2.3GHz was fine, with a second run based on the mooted 3.2GHz in the Gonzalo leak. I could also run this chip natively as both a quad-core and an octo-core part. The results are quite exciting:
|Cinebench R15 1T||Cinebench R15 MT||Octo-Core Score|
|Athlon 5370/1.6GHz||35||128||256 (Projected)|
|Athlon 5370/2.3GHz||49||183||366 (Projected)|
Clock for clock at 2.3GHz, Cinebench delivers a 2.24x improvement in single-thread erformance, and across four cores, it's a 3.4 times boost to performance compared to Jaguar. Factor in the mooted 3.2GHz frequency of Zen 2, and we're getting a 4.7 times improvement. Remember this is just one workload and limited one too, one that doesn't tap into the new architectural features of the Zen 2 core. Stacking up our projected octo-core Jaguar results against the 3700X with all cores and threads enabled and we retain the 4.7 times improvement to performance against our surrogate Xbox One X score, rising to 6.7 against our stand-in PlayStation 4. And just to stress again, this is an imperfect test - a very basic benchmark that just gives a small hint of the vast increase in performance we should get from the new consoles.
It's this huge boost to CPU performance that opens the door to the 120fps gaming Microsoft has promised in its Scarlett teaser, but more to the point, there's huge potential for far richer, more detailed game world simulations. And we shouldn't forget the solid-state storage solution found in both of the next-gen machines. Yes, we'll get faster loading, but more important is the proximity of a vast amount of data to the CPU and GPU. Games will evolve in very different directions because even if we compare the processor and graphics to the machines of today, I would expect the utilisation of those resources to be very, very different.
A generational leap is typically defined as a 6x to 8x improvement in performance, which makes the graphics side of things potentially more contentious. There is much we don't know about the GPU in PS5 or Scarlett - the compute unit count being a fundamental element. So instead, I decided to look at things on a more abstract level. The Gonzalo leak suggests a 1.8GHz or 2.0GHz GPU clock (I opted for the former), while the RX 5700 and 5700 XT deliver the same compute counts as PS4 Pro and Xbox One X. So what if CU count remains the same in the next machines, with performance bolstered by architectural improvements and that impressive leap in frequency?
To get some kind of handle on Navi's like-for-like boost in performance, we need games: titles that run with unlocked frame-rates and fixed resolutions, multi-platform in nature so we can match them up with the PC versions. And then we need to run those PC versions with the same visual feature set. We settled on two titles. Wolfenstein: The New Colossus on console is very, very close to the PC's medium settings, and can be configured to run with dynamic resolution scaling disabled. Meanwhile, Io Interactive helped us out by providing PC-equivalent settings to all console versions of the brilliant Hitman 2. While we can compare console to PC, console to console is less relevant: Pro runs at 1440p vs Xbox One X's 2160p in both cases. Meanwhile, Hitman 2 increases aspects such as anisotropic filtering and shadow quality in addition to the extra pixel count.
The results are fascinating, however. Stacking up 40 Xbox One X compute units against Navi at Gonzalo clocks, Wolfenstein 2 delivers improvements between 95 to 110 per cent of extra performance. Meanwhile, two Hitman 2 comparisons show an uptick of 82 to 83 per cent. Meanwhile, PS4 Pro vs Navi shows further boosts: Hitman 2 delivers 126 per cent more performance, while Wolfenstein 2 goes beyond that, with anything up to a 3.2x improvement to frame-rates. It's worth remembering here that developers have had issues with PS4 Pro in terms of available memory, plus an imbalance between compute power and bandwidth. This may skew some of the results more in favour of Navi, but with the likely move to GDDR6 in PS5, the improvement should be more profound than that seen moving on from Xbox One X.
After completing this exercise, I have a couple of takeaways. First of all, I think we're in safe hands for future console hardware: Zen 2 and solid-state storage are genuine game changers, and even if the GPU spec is less robust than RX 5700 or the XT I looked at here, the way the graphics core will be used will evolve in brand new directions, delivering new experiences. If we are indeed gifted a GPU capable of 2x Xbox One X performance, I'll be happily surprised, but even with more modest graphics, the possibilities are profoundly exciting.
Secondly, I think it's worth stressing how the arrival of PS4 Pro and Xbox One X may have skewed our expectations towards next-gen hardware - and at the silicon level at least, only so much can improve in a couple of years. PS5 and Scarlett are genuine successors to much older products: the base PlayStation 4 and Xbox One. In technological terms, they are old, they are starting to show their age - but even so, we're still getting stunning experiences like Uncharted 4, Horizon Zero Dawn, Forza Horizon 4 and Gears 5. Yes, PS4 Pro and Xbox One X deliver higher resolution versions of the same games, but they aren't the baseline - they're companion consoles, not the focus for development. PS5 and Scarlett constitute a new generation, a new baseline and a reset button pressed on the way games are made - while at the same time allowing developers to bring forth expertise from the last generation over to the next. I think we're in for exciting times.
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