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.


Xbox Series X internals

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
  Microsoft
Xbox Series X
Sony
Playstation 5
Capacity 1 TB 825 GB
Speed (Sequential Read) 2.4 GB/s 5.5 GB/s
Host Interface NVMe PCIe 4.0 x4 NVMe
NAND Channels   12
Power 3.8 W  

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.

Expandability

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.

Balancing the System: Other Hardware Features
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  • PopinFRESH007 - Tuesday, June 16, 2020 - link

    You could use GeForce Experience which does all of that for you if you don’t want to configure settings yourself. Assuming you have an nVidia GPU Reply
  • Zingam - Saturday, June 13, 2020 - link

    If they dip down to 30fps - that's intended. Blame your game developer. I used to be one. Reply
  • Kangal - Saturday, June 13, 2020 - link

    True.
    Although we've made a lot of progress in the console hardware:

    Small Capacity Cartridges > Much Larger CD > Much Faster DVD > Larger BluRay > Much Larger HDD > Much Faster SSD

    For example: SNES > PS1 > PS2 > PS3 > PS4 > PS5
    Reply
  • arslan0123 - Friday, June 26, 2020 - link

    look how good ps4 pro graphics are cuz games are optimized for 1 same hardware that millions owned. on PC there are lots of problems. u have to fix yourself. too much time consuming. on ps4 pro i dont have to care Reply
  • JStacts - Tuesday, June 30, 2020 - link

    Look
    because
    "1 same hardware" -> 1 standardized hardware set
    millions own
    On
    "u have to fix yourself." -> You have to fix these problems yourself.
    "too much time consuming." -> Too time consuming.
    On
    I
    don't
    .

    I might move on to your actual arguments, but I felt a translation was needed first.
    Reply
  • Sivar - Friday, June 12, 2020 - link

    Consoles are definitely easier to start with, but PCs have come a long way and still have "the PC advantages". You can buy any mid-range gaming PC or build one (if you like that kind of thing, as I do) with a mid-range nVidia card, mid-range CPU, etc. and install Steam and games generally "just work". nVidia provides software to automatically adjust game settings for your hardware.
    Load times, graphics quality, and controller quality are all superior on the PC, though new consoles generally take a brief lead before the multi-year period where PCs catch up and surpass them.
    For me, the mouse and keyboard alone will keep me on PC for the foreseeable future. The PC's game quality advantage is diminishing over time, but my types of games (RPGs with plots and characters, Warframe, and a few others) are still PC-centric.
    Reply
  • Zingam - Saturday, June 13, 2020 - link

    Mouse and keyboard, gamepads, light guns, VR, touch... are meant for completely different game types and experience. Mixing them is stupid. You don't play basketball with a golf ball as well you don't play golf with a football. Reply
  • close - Sunday, June 14, 2020 - link

    @Sivar: Of course PCs have advantages. From being potentially far more powerful than any console on the market, to easily being upgraded, and giving far more flexibility in the balance of performance and quality you can get. That's not really debatable.

    But the "just works and it's consistent and hassle free" will never come to the PC. The exact same arguments from above make sure of that. Consoles are uniform and it's much easier to make a game that plays just well enough on exactly that. You'd be hard pressed to find 2 identical PCs around. So if you really can't be bothered with that you'll give up on the advantages above to have something that for lack of a better description "just works".

    As an (offensive) analogy that the current gen of AT commenters will probably easily relate to, the PC is that hot Tinder date you have tonight. You always get the "latest model" and as long as you're willing to jump through some hoops and deal with some hassle you may get what you were looking for. Or maybe (s)he will just piss you off and leave you hanging. The console is your long term partner, not the best at everything, you can't just replace the parts you'd like changed but always there for you consistently delivering. And you love them for that. :)
    Reply
  • khanikun - Sunday, June 14, 2020 - link

    "But the "just works and it's consistent and hassle free" will never come to the PC"

    Except that it does, for some people. I just install the game and use whatever default it has and good to go. Maybe cause I'm not one of the ppl who are constantly grabbing the latest GPU drivers. I pretty much install the gpu with whatever the latest drivers were from that time and don't bother with updating it again.

    If you're the type that needs the latest chipset drivers, latest gpu drivers, latest firmware, etc. That way you can grab every ounce of performance out of the system or get the latest optimizations for X game, then Ya. You'll probably run into some kind of issues.

    If you get your machine running and don't bother with it again, you'll more than likely not run into any issues, except when you actually have a physical hardware fault. That or the game is just a piss poor port. Like the last Batman game.

    Me, I just game on both consoles and PC, cause I'm a gamer. Doesn't need to be one or the other.

    Also, I'll disagree with "You'd be hard pressed to find 2 identical PCs around". Are you completely forgetting OEM builds? You won't be hard pressed to find 2 identical PCs around. I bet you could find 1000 identical PCs around.
    Reply
  • shelbystripes - Friday, June 12, 2020 - link

    Your “penis measuring” mark makes me think you’re missing the point here. It’s true, there is a bunch of pointless fanboy-arguing between brand fans on each new generation about which is best. But this is AnandTech, and people come here to read articles about hardware, and HOW and WHY games on consoles are able to not only “just work as intended” but deliver impressive performance through incredibly thoughtful optimizations. What makes a GOOD console is that the final product “just works” but it’s still worth reading (for a lot of people) about the technology console makers are using to try to make that happen.

    This is especially true for the Xbox, where features being developed may influence PC gaming or Windows generally. The new Xbox storage API is going to make its way to Windows, and will be a much-needed improvement that could help more than just games.

    If you DGAF what’s inside a box, why are you on this site?
    Reply

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