If you watched Sony’s big PS5 reveal presentation today, you might’ve left drowsy and confused. Sony had intended to provide this presentation at GDC. In other words, the presentation is for developers and engineers, not to hype up the system for consumers. Even so, a bunch of fascinating technical details for the PlayStation 5 came out of the presentation, hosted by Sony’s chief system architect, Mark Cerny.
CPU and GPU
Sony did talk specs, and DigitalFoundry has provided more detail. The PlayStation 5 CPU is an AMD Zen 2 processor with 8 cores. The GPU is an AMD RDNA2 chip. The GPU has 36 Compute Units and squeezes out 10.28 TFLOPS. Cerny was careful to note, though, that not all TFLOPS are created equal. Cerny laid out a comparison of two fictional chips, one running with 36 CUs @ 1 GHz and one running 48 CUs at .75 GHz. The math has both of those coming out at 4.6TF of compute performance, but Cerny says those two chips would provide markedly different gaming experiences:
Performance is noticeably different, because ‘teraflops’ is defined as the computational capability of the vector ALU. That’s just one part of the GPU, there are a lot of other units – and those other units all run faster when the GPU frequency is higher. At 33 per cent higher frequency, rasterisation goes 33 per cent faster, processing the command buffer goes that much faster, the L1 and L2 caches have that much higher bandwidth, and so on… About the only downside is that system memory is 33 per cent further away in terms of cycles, but the large number of benefits more than counterbalance that.
Not All TFLOPS are Created Equal
One interesting thing here is that while the processors in our computers typically consume variable amounts of power and hold a steady frequency (or a base and boost frequency), the PlayStation 5 will keep the power steady and allow for frequency variability. The CPU will top out at 3.5 GHz, while the GPU caps at 2.23 GHz. The chips will generally run at these speeds most of the time, but can drop lower in a “worst-case game.”
In terms of a feature set, Cerny says the PS5 GPU will have similar features to that of AMD’s RDNA2 consumer line, including ray tracing through AMD’s Intersection Engine, and that that RT capability will be similar to that seen in PC gaming.
A few more PlayStation 5 specs
The PlayStation 5 has 16GB of GDDR6 RAM. The PS5’s memory runs at 448 GB/s across the board. Unlike the PlayStation 4 Pro, the system does include a 4K UHD Blu-ray drive.
The real monster here, though, is the SSD at the heart of the system. Cern said during his presentation that throughout countless conversations with developers, the biggest request was always an SSD.
The system features an 825 GB NVMe SSD, but it uses a custom flash that connects it directly to the main processor. The drive is capable of 5.5 GB/s. The strange size comes from the fact that this is a custom-built SSD designed to match the PlayStation’s capabilities and bandwidth needs. The SSD uses a four-lane PCIe 4.0 connection with what Cerny says is a lot of added customization to eliminate SSD bottlenecks.
Further adding to this speed is a new compression tool. The PS5 users ZLIB compression, which is the industry standard, but also supports Kraken, from a company called RAD Game Tools, which offers 10% more efficient compression. That translates to 8-9 GB/s in terms of raw performance.
Bring Your Own Storage*
Sony is taking a different route on expandable storage compared to that of Microsoft; where Microsoft is providing proprietary plug-and-play cards, Sony has an SSD bay in the system. You can put your own SSD in, but there’s a laundry list of caveats to that option. First, the drive has to fit. The bay has limited space, and some of the SSDs out there have huge heatsinks or even fans to keep them cool.
Further, Cerny says that commercial M.2 technology is way behind what’s happening in the PlayStation 5. For example, the PS5 SSD has six priority levels, but the NVMe spec only has two.
That means that even the speedy NVMe M.2 SSDs on Amazon right now won’t be up to snuff. It would either straight-up not work or cause constant performance hitches in PS5 titles.
*Certified by Sony
Instead, Sony will certify M.2 drives as being fast enough for the system. Don’t start stocking up just yet.
*Not certified for PlayStation 5
This is an interesting divide between Microsoft and Sony. Microsoft wants you to know that if you plug an expansion into your Xbox Series X, it’ll work. Sony gives you the option of picking up your own drive at your preferred capacity, but at significant risk that, if uncertified, it may not work.
Like the Series X, you can plug your own USB drive into the system to store and play PS4 games, but you won’t be able to play PlayStation 5 games off of these drives.
Cerny spent a good portion of the presentation talking about audio. This is something Cerny has harped on since the first reveal of the PS5 system. The PlayStation 4 (and Xbox One) does not have a dedicated audio chip. That means that every little piece of audio in every game fights for processor time and often ends up getting a fraction of a core on the PS4’s Jaguar CPU.
The Tempest 3D Audio Tech in the PlayStation 5 supports hundreds of audio sources. That’s compared to 50 in the PSVR headset and even less in the PS4 itself.
The system should be able to provide much more accurate audio positioning with higher-quality audio. Cerny said that the system is optimized for headphones right now, but that Sony is working on how the system will handle TV and surround speakers right now; more on that below. The system doesn’t require Dolby Atmos or anything like that to provide this high-quality positioning technology, either.
For Your Ears Only
Standard HRTF vs. Mark Cerny’s personalized HRTF
The biggest stumbling block will come from the speakers. The system will use something called Head-related Transfer Function to provide a more detailed audio experience, but everyone’s heads are different. This is something that Cerny says will evolve over the life of the console. They’ve modeled five custom HRTFs and a configuration tool for you to use to pick the best one for you. But eventually, Cerny wants to develop a way to help players develop personalized HRTFs that work for their ears and head shape. The current ones are based on tests with around 100 different people.
Cerny says that someday we might be uploading a photo of our ears or a video of our heads to Sony that would feed into a neural network to develop a personalized HRTF. This is all conjecture, not a promised feature set.
In short, Cerny is promising nothing short of a revolution with game audio.
Top-level details: MIA
Sony was short on other details. Cerny did not mention a price and release date, of course. Perhaps more surprising is that he didn’t show off the console or controller at all. Cerny did say that Sony has to test games one by one for compatibility with the PS5, as the system is too fast for some of them. The games then have to be tweaked, and Cerny didn’t say whether that’s up to the developer or to Sony to do. He did say that most popular titles will be playable at launch. Whether or not Sony supports this well remains to be seen.
There’s a lot to chew on here, and so far what it sounds like is that the PlayStation 5 and Xbox Series X are more different than the and Xbox One. They have a lot in common, but it’s tough to see who is going to edge out in performance.