Xbox Series X Storage Expansion Card revealed, promises performance match with internal SSD

Series X External
Series X External (Image credit: Microsoft)

What you need to know

  • The Xbox Series X Storage Expansion Card will hook up to the slot on the rear of the console.
  • Promises identical performance to the internal SSD.
  • 1TB custom solution built in partnership with Seagate.

As part of the massive data dump on the Xbox Series X the mystery of the storage expansion slot on the rear has been made a little clearer. The slot will be used for the Xbox Series X Storage Expansion Card (yes, what a mouthful), a custom storage solution built in partnership with Seagate.

Source: Microsoft (Image credit: Source: Microsoft)

Inside the console, we'll be getting a 1TB NVMe SSD for storage, but given how big games are going to get in the next-gen, this won't go very far. So, Microsoft has designed a solution to expand that without the necessity to go inside the console and start fiddling with things we shouldn't really be fiddling with. For now Microsoft has only officially confirmed a 1TB Storage Expansion Card, but apparently larger sizes should be coming in future.

It's not a replacement for external USB hard drives, as those will continue to be supported, but the Storage Expansion Card is promising identical performance to the internal drive, as this outline from Microsoft indicates (opens in new tab), recommending that Series X optimized games aren't played from a USB hard drive for optimal performance.

Built in partnership with Seagate, this 1 TB custom storage solution expands storage capacity of Xbox Series X with the full speed and performance of the Xbox Velocity Architecture Previous generation Xbox titles can still be played directly from external USB 3.2 hard drives. However, to receive all the benefits of the Xbox Velocity Architecture and optimal performance, Xbox Series X, optimized games should be played from the internal SSD or Xbox Series X Storage Expansion Card.

And as the Digital Foundry team points out, the Xbox Series X utilizes PCIe 4.0 to connect both the internal and external SSD storage directly to the CPU. So far we've only seen PCIe 4.0 used on AMD's X570 platform on PC, but the data speeds it's capable of are pretty spectacular so we're excited to see Microsoft make use of it in the Series X.

Xbox Series X/S


Richard Devine is an Editor at Windows Central. A former Project Manager and long-term tech addict, he joined Mobile Nations in 2011 and has been found on Android Central and iMore as well as Windows Central. Currently you'll find him covering all manner of PC hardware and gaming, and you can follow him on Twitter and Instagram.

  • Hopefully they're in a somewhat open standard. The original side mounted xbox 360 harddisk was a pain to deal with. Having xbox branded only 'Storage Expansion Card' rather than just a case that you can drop an nvme into will be a pain as well, and that's be such a shame. I already have a couple of nvme sticks from when I've upgraded. Not saying I'd use them if I got an xbox sx, but later on it would be nice to make use of existing hardware I have as upgrades.
  • It's more about the compatibility. These cards have identical performance to the internal drive and a direct PCIe 4.0 connection to the CPU. Whatever SSD you currently own most likely cannot offer the same performance. External SSDs and HDDs will still work. But sometimes you need a closed garden to make the experience actually work like it needs to.
  • "Whatever SSD you currently own most likely cannot offer the same performance." Please don't make unsubstantiated claims. Even 2.5" SSDs are comparable in small read/writes that games normally use. NVMe throughput excels in larger data transfers (server side) versus everyday gaming. PCIe 4.0 vs 3.0 benchmarks are readily available online and demonstrate nominal gains in every day use, such as gaming, compared to previous gen variants. Propriety storage is always about the money. Just ask Apple. The biggest takeaway is the RDNA2 architecture and nm size. This will be the most efficient console to date. However, 120fps 4k just isn't doable with that hardware. Likely 1080p 120fps and 4k 60fps are likely. Variable Refresh Rate will make gaming a joy on console. TV manufacturers tend to follow gaming trends and will undoubtedly meet demand.
  • Your missing the point. The CFExpress Cards have direct access to the CPU. A USB SSD won't. MS designed the card to operate exactly the same as the internal SSD does. Exactly. So if you install stuff on your Xbox external card, you will get the exact same performance. If you use a USB 3.2 SSD, it will not have direct access to the CPU. More hoops to jump through. So the performance won't be the same.
  • It would be nice if they can partner with Western digital because I don't trust Seagate for storage
  • So they are going with this proprietary 1TB SSD card? -_-
    No real option to add your own internal drive.
  • They have already taken their stand on adding internal storage to the Xbox, we kind of knew this wasn't going to happen. I'm not a fan of proprietary hardware. The best part about the XB1 solution was you could use ANY USB storage if it was big enough.
  • "On the storage side, the Xbox Series X comes with a custom 1TB NVMe solid state drive, which can be doubled by way of a proprietary expansion slot (that's right, memory cards are back). If upgrading the storage with the proprietary slot, Microsoft says speeds will be the same as the speedy internal SSD, so expect those to be expensive. Users can also add an external drive via USB 3.2 to store games on, but it won't run as fast, and you'll have to transfer games to internal memory to actually run them." I saw this on PC Gamer, the final line there is the most worrying and I REALLY hope it's not the case. The PC Gamer article also linked to Digital Foundry but I can't view Eurogamer at work, it's blocked, so I can't read the full write up.
  • Yeah, I kind of thought this was going to be the case as well. One would have to manually move games from their storage to play. I kind of do this already with an external SSD, but it's a pain, certainly not what I wanted to do with EVERY new game. My other thought was that the SSD might have been some kind Of system only storage like a hybrid HDD where the user can't choose to put things on it, but the system would use it as the player plays. I certainly like the actual SSD much better, even with the manual moving of files.
  • Of course it is true. The whole system is designed for fast loading and quick resume. You can't do those things by running the game from a USB 3.2 SSD. This is what happens with the latest tech. Older tech won't do the same job. Otherwise what really is the point in having SSD in the console costing all that manufacturing cost. May as well just use HDD and have load times 3 mins plus next Gen. I would imagine though transfer speeds for games from USB 3.2 SSD to internal SSD should be lightning fast as well. It's not like your transferring HDD to HDD. Also of note. DIGITAL Foundry talked about how MS can use the SSD internal storage as Ram. And explained how. There is 0 way of doing this via a USB 3.2 SSD. Developers can make their game and utilize the SSD as ram. By drawing straight from the SSD to the CPU. With no need for that info to go through the ram at all. So I can absolutely see why you can't run the game from the USB. It's a trade off. We want better games, bigger environments, etc etc. But to do that as well as Series X is you have to use new more expensive hardware. The SSD functionality of Series X goes way beyond simply faster storage. It's instrumental in balancing the system to give developers even more power and freedom of expression in their game designs. If you want to be an early adopter 1TB is the most we can have. To keep cost down. In a year or 2 they will have consoles with 2 or 4 TV internal as the cost comes down. Same with the card. DF again confirmed that 2 and 4 TB options will come after launch. If we don't want to be early adopters and pay for that priveldge of the latest tech. We can just wait a year or 2 and get a model with more storage room,
  • Actually it's the complete opposite to what you just said load times between a SSD and NVME are negligible. Transfer rates are hugely different. So actually transferring from an SSD to an NVME is much slower (for very large file sizes) because the SSD is a bottleneck but if you are running a game from an SSD as opposed to NVME you will barely notice a difference in load times (maybe 2-3 seconds). And seriously? If developers are using the internal storage for RAM they are SERIOUSLY crippling the system and it means the console was poorly designed, NVME is fast but it's not even close to being as fast as memory and like you said, the assets used in video games are only going to get larger. Basically they aren't going to do that, hell people only do that on PC if they have no other choice or don't know any better, swap files are the worst.
  • No they aren't crippling the system. Some of you need to go and watch all Digital Foundry videos on Series X. It's categorically a gane changer. As drawing straight from the SSD allows environments in realtime like the Hellblade 2 reveal. People were unsure how MS could get environments to look that good and realistic in realtime. Wel now you know. It's because they are able to draw environments geometry etc straight from the SSD. It's a big big deal. Without it, environments would be less detailed and smaller. It's explained in this one. It's nothing other than a huge advancement in game design. And is absolutely necessary to move game development forward.
  • I watched the video they don't talk about using the NVME storage as RAM at all, because, like I said, that's a terrible idea. It did actually seem like they weren't overly happy with the expandable cards, but they couldn't outright bad mouth something when they are standing in the office of the company that made it. But the dialogue and the way they were talking about the cards was noticably different to how excited they seemed when talking about the construction. I'm glad that Xbox One and 360 games will run from an external drive, hopefully that means if I run out of internal storage I can just run the "One X" version of a Series X game and not have to rearrange my software every gaming session. Nothing is perfect though, and this is the only disappointment I have with the upcoming system, so it's a minor grope. It's not the second coming though, there is nothing unique about the storage system at all, it's the same as PC has had since the Xbox One was released. It's going to be great to have multiple resume but if I can only store four or five blockbuster games on the internal drive that multi resume is suddenly a lot less interesting.
  • I told you a month ago they would do this. All that the "custom storage solution" means is a pre-set hardware encryption key on a chip designed and manufactured by Microsoft that is added to a standard NVME x4 SSD interface. This provides the hidden XBSEX key to standard BitLocker SSD encryption at the hardware level. If you use an external USB drive MS encrypts the data using the XBOX's internal bitlocker encryption keys, but this is more like their 4K Blu-Ray Optical drives where there is a custom encryption chip on the optical drive's circuit board.
    That will make it much faster than software encryption as it will leverage the AES-256 bitlocker support with their key. That is needed to "fingerprint" the drive to your XBSEX so you can't move your games to another user's XBSEX by pulling out the drive and taking it with you (although that would be cool if you could.)
    How much will it add to the cost? Hard to say, but knowing MS I suspect a steep premium over a standard 1 TB NVME SSD. The Seagate FireCuda 1TB NVME SSD is currently $150-$190 (depending on model) at Amazon, so I expect MS to charge at LEAST $250 for this. (Remember what they charged for the XB360 expansion drives?)
  • Yeah, this is the only thing I'm not happy about, because Microsoft are going to jack up the price on these things. I'll just get an external SSD drive when I need more storage though and won't use the port.
  • The question is about that is how using our externals will affect the games played off of them. I wonder if they will even address this in the E3 digital event.
  • I imagine games on a HDD will be ridiculously slow to load, but from an SSD should be fine.
  • I'm talking about it only using the new features of the system on the SSD or external cards rather than loading times.
  • Ah, ok, so things like the multiple resume and stuff? I replied to you above with a quote from another article I read, it's at Which also links to the Digital Foundry write up, but I can't view that at work.
  • Thanks, I will check it out. I really hope they give some information on this before release of the system.
  • Just like the N64!