Storage Matters: Why Xbox and Playstation SSDs Usher In A New Era of Gamingby Billy Tallis on June 12, 2020 9:30 AM EST
- Posted in
- Xbox Series X
- PlayStation 5
A new generation of gaming consoles is due to hit the market later this year, and the hype cycle for the Xbox Series X and Playstation 5 has been underway for more than a year. Solid technical details (as opposed to mere rumors) have been slower to arrive, and we still know much less about the consoles than we typically know about PC platforms and components during the post-announcement, pre-availability phase. We have some top-line performance numbers and general architectural information from Microsoft and Sony, but not quite a full spec sheet.
The new generation of consoles will bring big increases in CPU and GPU capabilities, but we get that with every new generation and it's no surprise when console chips get the same microarchitecture updates as the AMD CPUs and GPUs they're derived from. What's more special with this generation is the change to storage: the consoles are following in the footsteps of the PC market by switching from mechanical hard drives to solid state storage, but also going a step beyond the PC market to get the most benefit out of solid state storage.
Solid State Drives were revolutionary for the PC market, providing immense improvements to overall system responsiveness. Games benefited mostly in the form of faster installation and level load times, but fast storage also helped reduce stalls and stuttering when a game needs to load data on the fly. In recent years, NVMe SSDs have provided speeds that are on paper several times faster than what is possible with SATA SSDs, but for gamers the benefits have been muted at best. Conventional wisdom holds that there are two main causes to suspect for this disappointment: First, almost all games and game engines are still designed to be playable off hard drives because current consoles and many low-end PCs lack SSDs. Game programmers cannot take full advantage of NVMe SSD performance without making their games unplayably slow on hard drives. Second, SATA SSDs are already fast enough to shift the bottleneck elsewhere in the system, often in the form of data decompression. Something aside from the SSD needs to be sped up before games can properly benefit from NVMe performance.
Microsoft and Sony are addressing both of those issues with their upcoming consoles. Game developers will soon be free to assume that users will have fast storage, both on consoles and on PCs. In addition, the new generation of consoles will add extra hardware features to address bottlenecks that would be present if they were merely mid-range gaming PCs equipped with cutting-edge SSDs. However, we're still dealing with powerful hype operations promoting these upcoming devices. Both companies are guilty of exaggerating or oversimplifying in their attempts to extol the new capabilities of their next consoles, especially with regards to the new SSDs. And since these consoles are still closed platforms that aren't even on the market yet, some of the most interesting technical details are still being kept secret.
The main source of official technical information about the PS5 (and especially its SSD) is lead designer Mark Cerny. In March, he gave an hour-long technical presentation about the PS5 and spent over a third of it focusing on storage. Less officially, Sony has filed several patents that apparently pertain to the PS5, including one that lines up well with what's been confirmed about the PS5's storage technology. That patent discloses numerous ideas Sony explored in the development of the PS5, and many of them are likely implemented in the final design.
Microsoft has taken the approach of more or less dribbling out technical details through sporadic blog posts and interviews, especially with DigitalFoundry (who also have good coverage of the PS5). They've introduced brand names for many of their storage-related technologies (eg. "Xbox Velocity Architecture"), but in too many cases we don't really know anything about a feature other than its name.
Aside from official sources, we also have leaks, comments and rumors of varying quality, from partners and other industry sources. These have definitely helped fuel the hype, but with regards to the console SSDs in particular, these non-official sources have produced very little in the way of real technical details. That leaves us with a lot of gaps that require analysis of what's possible and probable for the upcoming consoles to include.
What do we know about the console SSDs?
Microsoft and Sony are each using custom NVMe SSDs for their consoles, albeit with different definitions of "custom". Sony's solution aims for more than twice the performance of Microsoft's solution and is definitely more costly even though it will have the lower capacity. Broadly speaking, Sony's SSD will offer similar performance to the high-end PCIe 4.0 NVMe SSDs we expect to see on the retail market by the end of the year, while Microsoft's SSD is more comparable to entry-level NVMe drives. Both are a huge step forward from mechanical hard drives or even SATA SSDs.
|Console SSD Confirmed Specifications|
Xbox Series X
|Capacity||1 TB||825 GB|
|Speed (Sequential Read)||2.4 GB/s||5.5 GB/s|
|Host Interface||NVMe||PCIe 4.0 x4 NVMe|
The most important and impressive performance metric for the console SSDs is their sequential read speed. SSD write speed is almost completely irrelevant to video game performance, and even when games perform random reads it will usually be for larger chunks of data than the 4kB blocks that SSD random IO performance ratings are normally based upon. Microsoft's 2.4GB/s read speed is 10–20 times faster than what a mechanical hard drive can deliver, but falls well short of the current standards for high-end consumer SSDs which can saturate a PCIe 3.0 x4 interface with at least 3.5GB/s read speeds. Sony's 5.5GB/s read speed is slightly faster than currently-available PCIe 4.0 SSDs based on the Phison E16 controller, but everyone competing in the high-end consumer SSD market has more advanced solutions on the way. By the time it ships, the PS5 SSD's read performance will be unremarkable – matched by other high-end SSDs – except in the context of consoles and low-cost gaming PCs that usually don't have room in the budget for high-end storage.
Sony has disclosed that their SSD uses a custom controller with a 12-channel interface to the NAND flash memory. This seems to be the most important way in which their design differs from typical consumer SSDs. High-end consumer SSDs generally use 8-channel controllers and low-end drives often use 4 channels. Higher channel counts are more common for server SSDs, especially those that need to support extreme capacities; 16-channel controllers are common and 12 or 18 channel designs are not unheard of. Sony's use of a higher channel count than any recent consumer SSD means their SSD controller will be uncommonly large and expensive, but on the other hand they don't need as much performance from each channel in order to reach their 5.5GB/s goal. They could use any 64-layer or newer TLC NAND and have adequate performance, while consumer SSDs hoping to offer this level of performance or more with 8-channel controllers need to be paired with newer, faster NAND flash.
The 12-channel controller also leads to unusual total capacities. A console SSD doesn't need any more overprovisioning than typical consumer SSDs, so 50% more channels should translate to about 50% more usable capacity. The PS5 will ship with "825 GB" of SSD space, which means we should see each of the 12 channels equipped with 64GiB of raw NAND, organized as either one 512Gbit (64GB) die or two 256Gbit (32GB) dies per channel. That means the nominal raw capacity of the NAND is 768GiB or about 824.6 (decimal) GB. The usable capacity after accounting for the requisite spare area reserved by the drive is probably going to be more in line with what would be branded as 750 GB by a drive manufacturer, so Sony's 825GB is overstating things by about 10% more than normal for the storage industry. It's something that may make a few lawyers salivate.
It's probably worth mentioning here that it is unrealistic for Sony to have designed their own high-performance NVMe SSD controller, just like they can't do a CPU or GPU design on their own. Sony had to partner with an existing SSD controller vendor and commission a custom controller, probably assembled largely from pre-existing and proven IP, but we don't know who that partner is.
Microsoft's SSD won't be pushing performance at all beyond normal new PC levels now that OEMs have moved beyond SATA SSDs, but a full 1TB in a PC priced similarly to consoles would still be a big win for consumers. Multiple sources indicate that Microsoft is using an off-the-shelf SSD controller from one of the usual suspects (probably the Phison E19T controller), and the drive itself is built by a major SSD OEM. However, they can still lay claim to using a custom form factor and probably custom firmware.
Neither console vendor has shared official information about the internals of their SSD aside from Sony's 12-channel specification, but the capacities and performance numbers give us a clue about what to expect. Sony's pretty much committed to using TLC NAND, but Microsoft's lower performance target is down in the territory where QLC NAND is an option: 2.4GB/s is a bit more than we see from current 4-channel QLC drives like the Intel 665p (about 2GB/s) but much less than 8-channel QLC drives like the Sabrent Rocket Q (rated 3.2GB/s for the 1TB model). The best fit for Microsoft's expected performance among current SSD designs would be a 4-channel drive with TLC NAND, but newer 4-channel controllers like the Phison E19T should be able to hit those speeds with the right QLC NAND. Either console could conceivably in the future get a double-capacity version that uses QLC NAND to reach the same read performance of the original models.
DRAMless, but that's OK?
Without performance specs for writes or random reads, we cannot rule out the possibility of either console SSD using a DRAMless controller. Including a full-sized DRAM cache for the flash translation layer (FTL) tables on a SSD primarily helps performance in two ways: better sustained write speeds when the drive's full enough to require a lot of background work shuffling data around, and better random access speed when reading data across the full range of the drive. Neither of those really fits the console use case: very heavily read-oriented, and only accessing one game's dataset at a time. Even if game install sizes end up being in the 100-200GB range, at any given moment the amount of data used by a game won't be more than low tens of GB, and that is easily handled by DRAMless SSDs with a decent amount of SRAM on the controller itself. Going DRAMless seems very likely for Microsoft's SSD, and while it would be very strange in any other context to see a 12-channel DRAMless controller, that option does seem to be viable for Sony (and would offset the cost of the high channel count).
The Sony patent mentioned earlier goes in depth on how to make a DRAMless controller even more suitable for console use cases. Rather than caching a portion of the FTL's logical-to-physical address mapping table in on-controller SRAM, Sony proposes making the table itself small enough to fit in a small SRAM buffer. Mainstream SSDs have a ratio of 1 GB of DRAM for each 1 TB of flash memory. That ratio is a direct consequence of the FTL managing flash in 4kB chunks. Having the FTL manage flash in larger chunks directly reduces the memory requirements for the mapping table. The downside is that small writes will cause much more write amplification and be much slower. Western Digital sells a specialized enterprise SSD that uses 32kB chunks for its FTL rather than 4kB, and as a result it only needs an eighth the amount of DRAM. That drive's random write performance is poor, but the read performance is still competitive. Sony's patent proposes going way beyond 32kB chunks to using 128MB chunks for the FTL, shrinking the mapping table to mere kilobytes. That requires the host system to be very careful about when and where it writes data, but the read performance that gaming relies upon is not compromised.
In short, while the Sony SSD should be very fast for its intended purpose, I'm going to wager that you really wouldn't want it in your Windows PC. The same is probably true to some extent of Microsoft's SSD, depending on their firmware tuning decisions.
Both Microsoft and Sony are providing expandability for the NVMe storage of their upcoming consoles. Microsoft's solution is to re-package their internal SSD into a custom removable form factor reminiscent of what consoles used back when memory cards were measured in MB instead of TB and before USB flash drives were ubiquitous. Since it uses all the same components, this expansion card will be functionally identical to the internal storage. The downside is that Microsoft will control the supply and probably pricing of the cards; currently Seagate is the only confirmed partner for selling these proprietary expansion cards.
Sony is taking the opposite approach, by giving users access to a standard M.2 PCIe 4.0 slot that can accept aftermarket upgrades. The requirements aren't entirely clear: Sony will be doing compatibility testing with third-party drives in order to publish a compatibility list, but they haven't said whether drives not on their approved list will be rejected by the PS5 console. To make it onto Sony's compatibility list, a drive will need to mechanically fit (ie. no excessively large heatsink) and offer at least as much performance as Sony's custom internal SSD. The performance requirements mean no drive currently available at retail will qualify, but the situation will be very different next year.
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Oxford Guy - Monday, June 15, 2020 - link"The other point is that PCs, while more complicated"
"Consoles" of today, except for the Switch, ARE PCs.
They are merely PCs with different walled gardens and, unlike the "PC" platform, they can't be used outside of those walled gardens. On the "PC", though, there is Linux, which offers freedom from the Microsoft and Sony taxes.
close - Tuesday, June 16, 2020 - link@hecksagon, this "oh it's just 30FPS" routine is pretty old. Whatever you think is a good resolution and framerate, someone thinks it should be higher. Current gen consoles play run games 4K@30-60FPS. *I* personally find that more than decent and certainly better than the hassle of PC gaming. And I say this as someone who plays on the console just slightly more than on the PC. Graphics are the bonus in a game, I still enjoy an "8 bit" game even without the Ks and the FPSs, I still play oldies.
So if you say rock solid 60FPS is good, someone can just reply "144FPS or bust, anything else is for micropeenuses" (got you there ;)). 4K is good? You need at least 4 x 5K monitors, anything else..." well you get the point. Maybe.
It's nice that you went on to list all the (dis)advantages that were already discussed previously by myself and others just before reaching the conclusion that for myself and many, many others the tradeoffs are worth it. But leave it to a 16 year old to think there's only room in this world for what they like "na-d'uh". You'd like to think that you're some sort of genius surrounded by millions of idiots who for some reason impossible to understand chose differently. Some day you might still want to play games but not feel like wasting your free time tinkering away.
So in conclusion yes, no matter how you measure it, mine is bigger ;).
FreckledTrout - Saturday, June 13, 2020 - linkWhile I am a PC gamer I do get the appeal of "it just works". I buy iPhone's because I don't want to deal with tweaking tons of with settings and iPhone's are fairly well configured right out of the box.
Oxford Guy - Monday, June 15, 2020 - link"While I am a PC gamer I do get the appeal of 'it just works'."
Marketing magic. In reality, there is nothing a "console" walled garden offers for consumers in added value. It's all smoke and mirrors.
Every feature can be done with Linux + Vulkan + OpenGL and done better (lower cost, less inefficiency of having THREE walled gardens).
close - Tuesday, June 16, 2020 - link@Oxford Guy "Every feature can be done with Linux + Vulkan + OpenGL"
Ah... all of the things nobody ever wanted to deal with when playing games. In reality you can't buy a console equivalent new PC for less money (plenty of people|bloggers tried and ended up comparing new consoles with second hand PC to even get close).
Yes, doing it yourself is many times cheaper, including (especially?) that thing that you mostly do by yourself. But people also want convenience. Which is why the lowly console still sells tens of millions of units every year. People even play on phones. And just as a hint that people don't care that much for your opinion... look around ;).
close - Saturday, June 13, 2020 - link@Retycint, nothing strange. Indeed, a game that is optimized by design to run as well as it can on the given hardware with no tinkering involved is for me far preferable than having to waste an afternoon for every game and maybe get the desired result. And just because you have dozens of settings and powerful hardware it doesn't change the fact that the performance will vary with every driver version. I've had a far more inconsistent gaming experience on my PC than on the console and again, I have a much faster PC than console.
Yes, there is the risk of a developer getting a game's performance to dip here and there. But then when this happens they usually fix it or the game stays on the shelves. I gave you a concrete example. For me and many others the tradeoff is worth it.
whatthe123 - Saturday, June 13, 2020 - linkexcept you gave a horrible example. Assassins Creed Odyssey dips in framerate on every platform, especially consoles, where neither the ps4 pro nor the xbox one x can maintain even 30fps as shown by digital foundry. Neither can maintain 4K either and instead use dynamic resolution, which is also available on PC. Basically your example of "it just works" is a game that constantly stutters from frame dips and can't maintain its output resolution. Not entirely sure how that's different from running a PC with random settings and just ignoring frame dips.
close - Sunday, June 14, 2020 - linkExcept my example wasn't "dips framerate", it was "freezes". I guess you can call it "dipping framerate all the way down to 0fps for at least 1s". And I guess you could argue that something is wrong on my PC, probably the AV doing something weird, when I installed the latest GPU drivers I didn't properly clean up the old ones, I didn't "defragment" the SSD, etc. But that would just reinforce my point.
I can give you dozens of examples but I'm sure you'll just find weird ways to "prove" that they are all exceptions that don't count somehow, "everyone knows that" . My GPU alone cost more than any latest gen console at launch, the rest of it is leaps ahead also, and yet the experience on PC was always more inconsistent and full of hassle.
And if you want to "play that game", every gamer worth their salt agrees that a playable experience starts at 144FPS but should really go higher. Which means your PC also spends 100% of its time in a "framerate dip". So if I'm going to stare at an "eyesore" I'd rather do it with a $400 box that mostly does 4K at 30-60FPS than a $2000 one where there's always a tweak to be done to get it right. I just don't have the time or the patience for that kind of crap. If the game review says "adequate performance" on the console, I know I'll get adequate performance. On the PC it's never that simple.
You clearly have no consistent first hand experience using both, so that kind of shoots your opinion in both feet and once between the eyes for good measure.
Zagor Te Nay - Sunday, June 14, 2020 - linkI'm with you.
Also PC and PS4 gamer. Not all games work perfectly on consoles, but if you do some research before you buy console game - wait for reliable review or two, for example - if conclusion is that game works fine on any give console, you know exactly what performance you will get out of it on your console. With PC, even with minimum/recommended specs, one never knows if game will behave exactly the same. There might be some legacy hardware, older drivers...
Back in the days - I think it was AMD64 days - I have built new rig with GeForce 7850 GPU etc. My PC was crashing in 2 out of 3 games. Game would freeze and audio would lock in a loop... hard reset was the only way out. Luckily I was working for IT company so I had access to spare parts I could borrow to troubleshoot.
After replacing everything meaningful, reinstalling OS and drivers a few times... and starting to get a bit desperate, I have replaced everything that I haven't tried before, just because. Solution to my problem turned out to be replacing Microsoft Internet Explorer keyboard. Keyboard was working perfectly in Windows, and computer never froze on desktop, so I never suspected keyboard. It probably wasn't even faulty - I brought it to office and it worked perfectly fine for years on my work PC, until I decided I don't want beige keyboard any more.
I know it is extreme one off, but I did have other share of smaller compatibility issues, since I started gaming on PC in early '90. Consoles are more straight forward.
SirPerro - Sunday, June 14, 2020 - linkWell but that's exactly it. "It just works" means that. That's what Apple users expect from their computer or phone. And you may not prefer consoles, but "They just work".
I also like PC gaming, but I'm aware there's A LOT of knowledge involved which is not necessary with consoles.
We are a small minority of people who understand really technical concepts. Power users if you want. But people out there don't know what frame rate is. They don't have a choice because it's overwhelming for them. That's EXACTLY what consoles do best. They create a layer of abstraction that works for too many people.