Xbox Series X SSD hard drive storage, from expansion cards to speed and size, explained

How Xbox Series X's super fast hard drive works - and how you can expand it.

The Xbox Series X's hard drive enables several of the console's new unique features.

Combining the SSD (solid state drive, where game downloads will be installed) within every console with various technologies under the banner of Xbox Velocity Architecture enables much faster loading times than previous console generations, as well as and quick resuming between multiple games.

Xbox has also confirmed how you can use Xbox Series X Storage Expansion Cards to give more hard drive space beyond what ships inside the console.

This page explains the Xbox Series X SSD speeds and features it enables as what to expect from the size and expansion options at launch.

On this page:

We know several other things about Microsoft's new console - including Xbox Series X specs, confirmed Xbox Series X games, the Xbox Series X controller details and the Xbox Series X console design.

How does Xbox Series X's SSD work, and what are the benefits over the Xbox One HDD?

As with the PS5 SSD, the Xbox Series X is built around a custom SSD solution.

This, combined with various 'Xbox Velocity Architecture' technologies, allow for more consistent load time performance and features unique to the console.

Here's what the Xbox Series X SSD provides:

  • The ability for the console to access 2.4 GB/s of data per second - or 4.8GB/s uncompressed - which is around 40 times than what's possible on Xbox One currently.
  • The headline benefit this brings is faster load times; Microsoft released a video of how State of Decay 2 runs on Xbox One X versus on Xbox Series X via backwards compatibility, with the previous generation console taking around 50 seconds, and the Series X 8-10 seconds:
  • The custom SSD is designed around "sustained performance" and not "peak performance", according to Microsoft. "Many PC SSDs 'fade' in performance terms as they heat up - and similar to the CPU and GPU clocks," explains Digital Foundry when breaking down the final specs, and so by having a new form factor, allows for more consistent performance. What does this mean in practice? It allows developers to plan and design for constant load and asset access times for their Xbox Series games.
  • The SSD storage to also used to augment memory through the various technologies under the 'Xbox Velocity Architecture' umbrella. "The idea, in basic terms at least, is pretty straightforward - the game package that sits on storage essentially becomes extended memory, allowing 100GB of game assets stored on the SSD to be instantly accessible by the developer," continued Digital Foundry in the breakdown - which also explains more about the other Velocity Architecture technologies technologies at play, from Sampler Feedback Streaming to high-speed hardware decompression, if you want the ins and outs of how this works:
  • A feature this enables is 'Quick Resume', where multiple games can be suspended mid-play and resumed within seconds. Microsoft released a video showing this in action using several Xbox One games through backwards compatible, and though the number of games supported in Quick Resume wasn't confirmed - likely due to the variation in memory each game would use up - a minimum of three Series X games will be supported:

How big is the Xbox Series X's hard drive storage?

The Xbox Series X will come with a 1TB Custom NVMe SSD at launch - in other words, 1,000 GB.

Not only is it much, much faster than any Xbox One's hard drive - even your own installed SSD, thanks to other Xbox Series X technologies designed to make the most of it - it's bigger than Xbox One launch model's hard drive size, which came in at 500GB.

Again, here's Digital Foundry with a comparison of what the Xbox Series X storage offers at a glance:

Xbox Series X Xbox One X Xbox One S
Internal Storage 1TB Custom NVMe SSD 1TB HDD 1TB HDD
IO Throughput 2.4GB/s (Raw), 4.8GB/s (Compressed) 120MB/s 120MB/s
Expandable Storage 1TB Expansion Card - -
External Storage USB 3.2 HDD Support USB 3.2 HDD Support USB 3.2 HDD Support

As you can see, it's possible to expand your storage is the default 1TB isn't enough. But how does this work exactly?

Interested in learning more about Microsoft's next console? Learn everything you need to know - from confirmed Xbox Series X specs and features and the console design, size, dimensions and ports and controller, through to Xbox Series X games, including those which support Xbox Smart Delivery. The Xbox Series X will also support the ongoing library of Xbox Game Pass games.

How you can expand Xbox Series X storage with Expansion Cards

With the bespoke SSD for Xbox Series X comes a surprisingly old school solution for adding more hard drive space - expansion cards.


The approach of Xbox's Storage Expansion Cards feels closer to memory cards from 2-3 console generations back than a traditional hard drive, and offers the same performance as the internal SSD included with every Xbox Series X.

At launch, Seagate will be the official provider of Xbox Storage Expansion Cards, with a 1TB card available for purchase by the end of 2020.

According to Digital Foundry, Xbox Storage Expansion Cards feel "rather heavy, likely down to the solid metal construction" which helps keep the temperature, and in turn performance, consistent.


As well as this, traditional external USB hard drives are also supported.

Like with the PS5's external hard drive support, this will only support Xbox One, Xbox 360 and original Xbox backwards compatible games, allowing you to keep the more valuable SSD storage for next-generation games.

Want to read more about the Xbox Series X? You can read our list of all confirmed Xbox Series X games, as well as Xbox Series X specs, the Xbox Series X console design and the Xbox Series X controller.

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Matthew Reynolds

Matthew Reynolds

Guides Editor

Matthew edits guides and other helpful things at When not doing that, he's out and about playing Pokémon Go or continuing to amass his amiibo collection.


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