PS5, Xbox Scarlett SSD may use Optane-like ReRAM to supercharge speeds

Next-gen consoles may use Optane-like cache modules to supercharge SSD speeds and keep storage costs low.

14 minutes & 19 seconds read time


Sony and Microsoft may use PCIe 3.0 SSDs in tandem with Optane-like cache technology to accelerate data in their next-gen consoles, leading to massively improved load times, revolutionary asset management for developers, and lowering the console's overall price point for consumers. Or they could use tiered storage to combine an HDD and SSD as a cost-effective solution that doesn't sacrifice speeds.

PS5, Xbox Scarlett SSD may use Optane-like ReRAM to supercharge speeds 9

We originally thought Sony and Microsoft would use new PCIe 4.0 SSDs in their next-gen PlayStation 5 and Project Scarlett consoles. We've heard both companies rave about their ultra-fast storage, and PCIe 4.0 can hit up to 32GB/sec transfer rates on 8x lanes. But this seems like overkill. Although the Zen2+ chips in next-gen consoles natively support PCIe 4.0, Sony and Microsoft may not really need to leverage it.

They could stick with PCIe 3.0 over NVMe or even SATA drives and still have a noticeable jump from current mechanical HDDs. PCIe 4.0 SSDs are pretty expensive, and if included in new consoles, the PS5 and Scarlett may not hit their rumored $499 price tags.

So if the PS5 and Project Scarlett don't use PCIe 4.0 to hit insane speeds, what will they use? There are some possibilities. We could see a single M.2 NVMe PCIe 3.0 SSD, or a hybridized SSD and HDD with tight cohesion and synergy with other components via tiered storage.

We could even see a custom onboard cache module similar to Intel's Optane tech, and it just so happens Sony is developing its own ReRAM SCMs.

Before we can talk about what PlayStation 5 and Project Scarlett's storage will be like, we have to understand how caching and tiered storage works, and how it's advantageous for current system builds.

Fair warning, this is a big article, and there's a chance we're completely wrong about this.

Cached memory acceleration: Next-gen's secret storage sauce?

The secret with the PlayStation 5's and Project Scarlett's ultra-fast SSDs might not lie with the actual PCIe generation of the drives themselves, but how that storage is optimized with software and additional hardware, such as cache modules.

The storage in next-gen consoles could end up utilizing something very similar to Intel's Optane M.2 modules. This might be somewhat expensive and nullify the cost-effective argument against PCIe 4.0, at least for the custom module solution, but it could also supercharge data speeds at relatively low capacities.

We know that Optane won't actually be used in next-gen consoles (which, of course, are powered by AMD), but we'll use it to demonstrate how this tech works and what it means for gaming.

Intel's consumer-available Optane modules have one simple premise: To make your most frequently-used data load faster.

PS5, Xbox Scarlett SSD may use Optane-like ReRAM to supercharge speeds 6

Read Also: Intel Optane Memory: What It Is and Why It Matters

The stick determines what programs and data you access and use the most, and prioritizes the data by caching it on Intel's proprietary 3D XPoint memory. That way, the CPU can access the data directly, which is great news for developers, especially when they need to rapidly move huge scattered blocks of data.

This is called memory caching. It's different from tiered storage, which we'll get to later on.

These types of modules were meant to complement existing storage, not replace it. They can sit in a build with multiple drives, including a setup with an HDD and SSD solution, whereby the HDD's speed is somewhat counteracted by the fast caching of the module and the SSD's overall data rates.

Optane is a cache memory stick with built-in DRAM and storage memory that sort of bridges communication between storage, processor (CPU, GPU), and system RAM. It streamlines the system in a more direct and seamless path to maximize speeds, and stores often-used data from the SSD onto its memory cache, which is then fed directly to the CPU itself.

"When this new memory media is installed between the processor and slower storage devices (SATA HDD, SSHD, SSD), the computer can store commonly used data and programs closer to the processor. This allows the system to access this information more quickly, which can improve overall system responsiveness," Intel says about its Optane modules.

Remember, these kinds of modules only hold the prioritized data on its cache, whereas the bulk of your system's data is stored on another drive, whether it be mechanical HDD or NAND SSD (or both). Optane isn't storage, more of a kind of memory card that holds the most important data.

The 3D Xpoint memory in Optane is Intel's own version of an SCM, or storage-class memory, which is typically used in enterprise servers to cache immense data loads.

Sony has its own SCM solution using ReRAM, or Resistive Random Access Memory, and it could be the secret sauce behind the PlayStation 5's ultra-fast solid state drive.

Sony could use ReRAM to boost PS5 SSD speeds

ReRAM is a type of non-volatile RAM that has tremendous advantages over NAND memory like consuming less power, scalability into smaller form factors past 15nm, can be stacked with 3D cross-point arrays (hence Intel's XPoint memory), and it's also far more durable than flash memory.

Unlike DRAM, which stores a charge, ReRAM creates resistance by passing an electric current through two types of materials, which is then read as a 1 or a 0.

Sony has been working on its own ReRAM solutions since 2013, when it teamed up with Micron to start developing 16Gb chips, and now expects to start shipping ReRAM solutions in 2020 for the enterprise market.

We could see Sony's ReRAM modules being used or adapted in the PS5 to accelerate speeds dramatically.

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ReRAM would essentially work like an Optane module, storing the most-used files and data blocks on its built-in cross-point RRAM memory cells as cached data, and then beaming them directly to other system components like the GPU and CPU for processing.

The idea is that Sony would pair its ReRAM modules up with an SSD to accelerate overall data loading by means of super-fast caching.

ReRAM wouldn't need to replace the PlayStation 5's SSD but work alongside it. This way, Sony could use cheaper 2TB NVMe PCIe 3.0 drives or even SATA drives to ensure the PS5's purported $499 MSRP.

Sony could theoretically make an entire SSD drive out of ReRAM for the PlayStation 5, but that'd be quite costly and might produce some serious heat. It's pretty unlikely to see a whole ReRAM SSD just for the PlayStation 5. If anything, we'll probably see a separate smaller module fastened to the PS5's motherboard that boosts SSD speeds, as we outlined above.

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Sony recently outlined some details on its ReRAM in a big presentation at the Persistent Memory Summit 2019 show.

Sony is targeting 128GB and 256GB capacities for its ReRAM SSDs. Remember, these are fully-fledged SSDs, not a smaller module. These capacities could be overkill for the PlayStation 5 both in price and performance, and we should see smaller chips being made special for the console.

Using PCIe 5.0 on x16 lanes, Sony's ReRAM SSD drives are expected to hit the following speeds:

  • 128GB (8x 128Gb) - 25.6GB/s read, 9.6GB/s write
  • 256GB (16x 128Gb) - 51.2GB/s read, 19.2GB/s write

Again, the PlayStation 5 won't hit theses speeds. These are higher-end ReRAM-enabled SSDs made specifically for the enterprise market.

There are some concerns, though. Right now, ReRAM can require more power than DRAM (at least in these higher capacities), and Sony says they have to be cautious to the memory controller while designing ReRAM solutions for small-form-factor systems, which likely include the PS5.

This kind of solution would enable fast game startups, quick data loading, and it would also speed up data rates on older mechanical HDDs or SSDs--which is perfect for anyone who holds most of their console games on an external drive.

"The raw read speed is important, but so are the details of the I/O mechanisms and the software stack that we put on top of them. If I got a PlayStation 4 Pro and then I put in a SSD that cost as much as the PlayStation 4 Pro-it might be one-third faster," Sony's Mark Cerny said in an interview with Wired.

Speed isn't everything, though. PlayStation 5 architect Mark Cerny confirms the new ultra-fast SSD will come with customized software on the OS level that allows for hybrid data installs. This means gamers could theoretically choose what portions of a game they want to install, dramatically reducing install sizes.

The PlayStation 5 will support massive 100GB BD-XL Blu-ray discs, which is great because games are getting monstrous. Thankfully we can carve up the choice bits and only install, say, multiplayer, or the campaign of a game.

"Rather than treating games like a big block of data, We're allowing finer-grained access to the data," Cerny told Wired.

Tightening up shared hardware synergy with cache acceleration

The potential here is tremendous, especially for a closed ecosystem like a console with unified system components and a customized OS.

Consoles typically share RAM and VRAM in the same memory pool accessed by the onboard APU, and in this case, both PlayStation 5 and Project Scarlett will use a Zen 2 CPU and Navi GPU on the same SoC with built-in GDDR6 system memory.

Unified by Optane-like or ReRAM cache acceleration tech, the storage drives will join the CPU, GPU, and DRAM pool (in this case, VRAM and DRAM are shared) to directly feed the components with important data.

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Both the GPU and CPU would benefit from quicker data access, allowing for the PS5's insane 0.8 second loading times in Spider-Man as well as speedy access to game textures, environment assets, and rendering effects. Texture pop-in might be a thing of the past, thanks to this storage tech.

Speaking of system memory, the cache tech can also recruit RAM to supercharge data speeds even more. Apparently, Microsoft has taken this a step even further.

They recently confirmed they're using Project Scarlett's SSD as a VRAM buffer, which is something that Optane and ReRAM modules can apparently do. Optane can't really replace RAM, but it can complement existing system RAM to boost performance. Since DRAM and VRAM is shared in the console environment, this seems entirely within the realm of possibility for cache-accelerated next-gen console storage.

"We've created a new generation of SSD. We're actually using the SSD as virtual RAM. We're seeing more than 40x performance increases over the current generation," Microsoft said in the Project Scarlett E3 2019 reveal video.

"The combination of the SoC and the solid state drive are really what gives you a totally new experience."

"Now we can take all of that power and apply all of that back into the scene, and generate more life into that world and bring it to the gamer in a seamless way."

There's another possibility: Both the PlayStation 5 and Project Scarlett could use tiered storage, which would allow lower-cost, high-capacity HDDs and high-speed SSD combos in the systems.

StoreMI and tiered storage

StoreMI isn't a complete hardware-and-software package like Intel's Optane. Optane is an actual stick with onboard 3D NAND memory, whereas AMD's StoreMI is just software. We talked about Optane so much because it illustrates both the hardware and software points, and both might be used in next-gen consoles.

StoreMI also utilizes tiered storage, which is different from the cache method that Optane uses. Tiered storage is a method of combining two separate drives into one virtual drive.

Enterprise machines typically use tiered storage to combine slower mechanical HDD drives with faster SSDs drives to keep costs down while not tremendously jeopardizing speed.

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PS5, Xbox Scarlett SSD may use Optane-like ReRAM to supercharge speeds 1

StoreMI is software that AMD licensed from an enterprise company called Enmotus, and it comes with the AMD X470 chipset for Ryzen desktop processors. It could come natively installed on PS5 and Project Scarlett hardware too.

StoreMI essentially unifies your storage into one big package and hybridizes your drives into a big pool of available storage. So if you have a 2TB HDD and a 250GB SSD, StoreMI links the two and the operating system recognizes one drive with 2.25TB of storage.

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StoreMI speed comparisons of an WD Blue HDD and Samsung SSD 860 Evo (Credit: Gadgets360)

Your new virtual drive won't magically ignore the lower speeds of the HDD, of course, and it won't typically be as fast as an SSD on its own, but the speeds don't drop all that much.

"If you are adding an SSD to a system with an HDD, the system will perform at SSD speeds. If you are adding an HDD to a system with an SSD, the system will continue to perform at SSD speeds, but you will enjoy the added capacity without needing to manually manage data across both drives."

As with Optane, StoreMI uses a machine-learning algorithm to prioritize important files. But StoreMI doesn't cache anything; instead it moves prioritized data from slower storage (HDD) to the faster storage (SSD) to allow speedier access. This would translate to faster load times in games as well as speedier texture pop-ins, asset loading, etc.

So why would Microsoft and Sony opt for this solution? It's simple: To save money on storage without having to give up higher speeds.

Here's how AMD explains StoreMI in laymen's terms:

"StoreMI kind of gives you the capacity of your hard drive with the speed of your SSD," AMD's Robert Hallock said in a walkthrough video.

"StoreMI merges your drives into one single storage device. What StoreMI does is looks at the files that you use most often, looks at what blocks of those files are being loaded most often, and then starts migrating them from the hard drive to the SSD.

"So, you have all the capacity of both drives, but you get the speed of your SSD in the files, or programs, that you use the most.

"The next thing StoreMI can do is pull in a little bit of RAM. We'll pull in about 2GB of RAM into this equation as well. So now I have the capacity of a hard drive, the speed of an SSD, and the super speed of memory. So now we get supercharged from the RAM as well."

With the drives unified and recruiting RAM to boost speeds, the entire system is now communicating in a more deeply-connected way. The onboard GDDR6 RAM could drastically accelerate data. Remember that consoles reserve a portion of RAM for OS usage, and its this pool the system could tap to supercharge data transfers from storage to the APU.

PS5, Project Scarlett: SSD + HDD duo?

Now that we know how cache-acceleration and tiered storage works, and their potential, let's talk about what next-gen console storage could look like.

AMD has StoreMI, its own tiered storage software, but if the companies go with a cache solution, there's something missing: The actual modules themselves. This would have to be filled by OEMs, at least on Microsoft's part. Luckily OEMs are working on ReRAM solutions, including WesternDigital.

But Sony is making its own ReRAM solutions, and it's very likely the PS5 will have a built-in cache acceleration module similar to Intel's Optane solution, at least in practice.

With ReRAM persistent memory, the PlayStation 5's storage setup could look like this:

  • 32GB - 64GB of ReRAM cache memory
  • 1-2TB NVMe or even SATA SSD

Samsung also hinted that it'll provide the PlayStation 5's NVMe SSDs, and the same could be true for Microsoft.

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With this setup, the PlayStation 5 and Project Scarlett systems would have easily expandable memory--hooking up an external SSD or HDD would tap the onboard ReRAM modules--and allow for easy internal SSD swaps. Well, at least for the PlayStation 5. Swapping out the Xbox One's internal drive is a nightmare.

It's also possible both Microsoft and Sony could just ship consoles with both an HDD and SSD, without an actual caching module to reduce costs. This could use the tiered storage approach with StoreMI.

Tiered storage solutions could look a little something like this:

  • 1-2TB mechanical HDD
  • 256GB NVMe PCIe 3.0 SSD (max capacity supported by StoreMI without buying into the FuzeDrive software upgrade)
  • Both drives unified with AMD's StoreMI technology

StoreMI does seem unlikely, though. There are discrepancies between the HDD and SSD, and other problems like the 256GB SSD cap without buying into the FuzeDrive upgrade. The biggest roadblock is adding a new drive.

As for expandable drives, this could get tricky. Since StoreMI fuses two drives together, AMD confirms that StoreMI only works with two physical drives. It also doesn't work with any drives attached via USB--only SATA or NVMe. Anything more than two drives won't actually reap the benefits of the hardware.

If StoreMI is used, then gamers may have to copy their games from an external device over to the actual console storage to get the benefits of the software. Otherwise, the data would be based around the external storage's speeds and wouldn't enjoy the prioritization boost.

The solution could be AMD and Enmotus developing a special version of StoreMI specifically for consoles, allowing for more specially-formatted drives to be connected to the system. The same could be true for Project Scarlett.

Again, this is pretty unlikely. But we thought tiered storage was interesting enough to mention in this article.

Conclusion: There's still many unknowns

No one really knows what Sony and Microsoft are up to. These are just speculations based on the current tech and storage-optimization software on the market today, so by no means take any of this as fact.

Admittedly some of the info here reaches pretty far, especially the StoreMI tiered storage solutions. But based on everything we've read and seen so far, it seems likely both next-gen systems will use cache acceleration modules using ReRAM to dramatically boost loading times, as well as allow developers to use onboard SSD memory as a VRAM buffer for their games.

Check below for more info on the PlayStation 5 and Project Scarlett next-gen systems:

Sony is expected to reveal the PS5 in a special event in February 2020. The console will release in Holiday 2020, and it may cost $499.

PlayStation 5 specs and details

  • Custom SoC with second-gen Navi GPU, Zen 2 8-core, 16 thread CPU
  • Navi, Zen SoC uses new AMD RDNA 2.0 architecture
  • Ultra-fast SSD
  • Support for 4K 120 Hz TVs
  • Ray-tracing enabled
  • 8K graphics support (probably video, not gaming)
  • Plays all PS4 games
  • Separate games that ship on BD-XL Blu-ray discs
  • New controller with extensive haptic and tactile feedback

Project Scarlett is due out by Holiday 2020. No pricing has been announced.

Project Scarlett confirmed details:

  • 8-core, 16-thread Zen 2 CPU
  • Navi GPU
  • Highly customized 7nm SoC from AMD
  • GDDR6 memory
  • 4x as powerful as the Xbox One X's 6TFLOPs of perf
  • Can deliver up to 40x more performance than Xbox One in specific use cases
  • Adaptive sync supported
  • Super-fast SSD that can be used as VRAM
  • Supports 8K resolution (likely media playback)
  • 120FPS gaming
  • Variable refresh rate
  • Raytracing confirmed with dedicated raytracing cores
  • Backward compatible with Xbox, Xbox 360, and Xbox One games
  • Compatible with Xbox One accessories

PlayStation 5 Coverage:

Project Scarlett coverage:

Derek joined the TweakTown team in 2015 and has since reviewed and played 1000s of hours of new games. Derek is absorbed with the intersection of technology and gaming, and is always looking forward to new advancements. With over six years in games journalism under his belt, Derek aims to further engage the gaming sector while taking a peek under the tech that powers it. He hopes to one day explore the stars in No Man's Sky with the magic of VR.

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