It looks like the strange port on the back of the Xbox Series X is for expandable storage

Xbox Series X
Xbox Series X (Image credit: @Doug_DragoX)

The back of the Xbox Series X leaked in a series of pictures recently, giving us a better look at what features we can expect from the console. It was thought for a time that the strange strip port at the top center in the picture above was for high-speed debugging tools, but it seems that isn't the case.

On my podcast The Xbox Two (at 53:05), I recently talked about how I was investigating the possibility that the larger port was, in fact, an expandable storage port for CFExpress SSD cards, giving users a way to expand their storage capacity on the Xbox Series X without losing the rapid loading speeds that will come with the NVMe internal drive. Today, Brad Sams noted that he'd heard from sources familiar with Microsoft's plans that it is indeed for expandable storage. I can also confirm at my end that Microsoft is testing CFExpress cards using this port.

What is CFExpress?

Source: Prograde (Image credit: Source: Prograde)

CFExpress is an SSD storage solution, typically used with higher-end cameras. It uses PCIe lanes to achieve up to 4GB/s read speeds, although it is very expensive as of writing, with 128GB cards costing anywhere up to $200. (opens in new tab) You're barely going to be able to store one 4K game without ponying up for a larger card, which run up to $600 (opens in new tab) for just 512GB of storage.

Is it economically viable to be offering this sort of storage solution? There are a few possibilities. First of all, Microsoft may be licensing the tech to sell their own storage devices in bulk, possibly helping to reduce costs. Second, the cost of technology generally decreases over time. The first 4K OLEDs went on sale for $10,000 a few years ago, now they're far cheaper. SSD costs, in general, are coming down, and if Microsoft (and to speculate, Sony) are looking to adopt CFExpress as the standard for storage expansion for next-gen consoles, it could help drive costs down too. At launch, though, it seems likely that these cards will be pretty expensive, but the option will be there for those who can afford it, and don't want to suffer the external USB storage speeds we're using today.

In any case, it probably won't be long until Microsoft confirms once and for all that the port is indeed used for expandable storage options, particularly with the Game Developer's Conference on the horizon. Always take these sorts of rumors with a pinch of salt, but this one is looking pretty airtight.

Xbox Series X/S


Jez Corden
Co-Managing Editor

Jez Corden a Managing Editor at Windows Central, focusing primarily on all things Xbox and gaming. Jez is known for breaking exclusive news and analysis as relates to the Microsoft ecosystem while being powered by caffeine. Follow on Twitter @JezCorden and listen to his Xbox Two podcast, all about, you guessed it, Xbox!

  • Just make a easily removable cover where we can add a PCIe SSD. Same thing for increasing RAM, or even swapping out the RAM for faster RAM at a later date.
  • I was the one who floated that theory at Brad, based on a LinkedIn profile on something you tweeted showing that the Phison PS5019-E19T was being used in the Series X. So you were indirectly the reason I went down that rabbit hole. It sure does make sense though, given what we know. Interesting to see that it's actually panning out to be true.
  • Thanks buddy. I was recently told by a couple of sources that there are cards being shipped out to some testers/devs and they're based on CFexpress, I wasn't gonna write it up until I had better proof/photographs of the cards maybe, but Brad's separate sourcing is good enough for me. Seems bang on.
  • I'm still wondering if they're also going to allow external HDD storage using AMD's StoreMI tech. I could see them intelligently swapping things on/off the HDD to the faster SSD as needed the way StoreMI does on PC. A lot of people are sleeping on some of those features of the newer AMD processors and boards.
  • I suspect they will launch with 1TB, which is a real shame. Should be 2TB as a minimum, then allow this also. 1TB isn't that huge now, but with higher res assets and the like, 2TB should be the least we need. Also, 1 comment on the podcast, I love it, but can you have some moving images? Terrified that I'll get that centre circle burned into my OLED.
  • They pretty much HAVE to right? 1TB SSDs are pretty expensive (though not like this expandable crap), so I can't imagine they would put a 2TB unless this thing is over $1K.
  • Damn, sorry, posted a fresh comment, instead of a reply. Hope they do go for 2TB, or at least have the option.
  • I hear you, but crikey, the thing will hold probably 8 AAA games, plus OS, plus coach zone. Brad even, though I am sure he mis spoke, or I misheard him, say something about a tradition 1TB... Not SSD. As I say, sure it is an error form me or him. SSD is table stakes for the next gen.
  • Maybe they will have both types of storage internal since the SSD is supposed to be used as virtual RAM. This would mean the SSD is probably going to be pretty small which may make more sense for pricing.
  • Hmmm. That slot looks almost like a perfect fit for a M.2 2230 size SSD in a custom carrier.
    Remember, the Surface X uses these now behind a plastic access door.
    They are still NVMe, but a lot smaller.
    You can buy plastic carriers for them right now for about $20 so MS could be creating one for a few $ easily.
    That sounds a LOT more possible, and a lot cheaper to procure and sell.
  • Besides upgrading SSD, I would love to be able to upgrade RAM like we did on the N64.
  • It worries me a bit, this culture of leaks and stolen prototypes and corporate secrets. The device hasn't been released and we know where all the ports are like, where they are, etc. We don't need any of that, trust me.
  • I'm almost positive this is a controlled leak. The sort the company allows on purpose.
  • I doubt this port will make it to retail kits. Surprised l will be. Who cares anyway?
  • Who cares about adding storage to their system? Is that a serious question?
  • It's fairly officially for debugging purposes.
    Sources; like 5 places a week ago
  • Yes, because all news on unannounced hardware has always been 100% correct off the bat and is never corrected over a month closer to the release date...
  • Still lacks an HDMI IN. Which makes the console a non-starter for me.
  • Lol nice. /troll