Console storage: Switch 2, Xbox, Steam Deck

Three consoles, three different answers to "just put a card in". The only thing they agree on is that the wrong card makes you very good at deleting games.

The short answer

What storage can you add to a Switch 2, an Xbox Series X|S and a Steam Deck? Per the makers' own pages, as of 25 Oct 2026: the Switch 2 accepts only microSD Express cards, up to 2 TB [1][2]. The Xbox Series X|S accepts a Storage Expansion Card that plays every kind of game, and USB drives that store Series X|S games but cannot play them [8][10]. The Steam Deck takes a normal microSD card (UHS-I) that it formats itself [12][14]. The Steam Deck's internal SSD is an M.2 2230 module that Valve calls "not intended for end-user replacement" [13]. Match the card to the console first, then think about size. Our assessment: nearly every wrong purchase here comes from assuming that a card or drive that works in one console works in the others.

How it works

1. Start with what you want on the extra storage. Games, updates and downloadable content are one thing. Save data, screenshots and the system itself are another. The three makers treat these differently, and the table in your head should have three columns: what the console accepts, what can live there, and what still stays inside.
2. Nintendo Switch 2: microSD Express only. Nintendo states that the Switch 2 is only compatible with microSD Express cards and that cards used on the original Switch cannot be used for anything but importing screenshots and videos [1][2]. The console has 256 GB of its own storage, of which a portion is reserved for the system [3]. Any card up to 2 TB that meets the microSD Express standard can be used [1]. Cards are sold separately [1]. A system update over the internet is required the first time you use one [2]. A card can hold downloadable software, software updates, DLC, screenshots and captured videos [1]. Game save data stays in the system memory and cannot be copied to the card [1][3]. Nintendo Switch Online members can use Save Data Cloud for supported titles [3]. Once a card is inserted, it becomes the default save location for downloadable software [1]. Nintendo recommends one card per console: downloadable software spread over several cards cannot later be combined on one card, but you can copy everything to a larger card [1]. External USB hard drives are "not currently supported" per Nintendo's FAQ (as of 25 Oct 2026) [3]. Nintendo names no individual games that need extra storage "at this time" [3]. The reverse also works: a microSD Express card can be used in an original Switch, but there it reads and writes at the speed of a normal microSD card [2].
3. What "Express" means. The SD Association describes microSD Express as a card that adds the PCIe and NVMe interfaces, the same ones used by SSDs, on a second row of pins, and keeps the legacy microSD interface for backward compatibility [6]. It lists 985 MB/s for microSD Express under SD 7.1 (PCIe Gen3 x1) and 1970 MB/s under SD 8.0 (PCIe Gen4 x1), against 104 MB/s for the UHS-I mode SDR104 [5]. The association also says the maximum speed differs from the bus speed and varies with the card, the device and how the card is filled [5]. Our assessment: these are ceilings, not what a game will see. Nintendo publishes no speed figure for the Switch 2 slot in the pages we read, so how fast the console actually reads a card is unverified.
4. Xbox Series X|S: three kinds of storage. Microsoft says the consoles come with a 512 GB or 1 TB internal SSD and that you can add space by uninstalling games, connecting an external hard drive or adding a storage expansion card [7]. The expansion card plugs into a port on the back of the console and works with both the Series X and the Series S [8]. Microsoft's Xbox Wire explains that it was built with Seagate to deliver the same sustained performance as the internal SSD, that you can play games straight from it and that Quick Resume works from the card, from the internal SSD and from USB drives [8]. In October 2021 Microsoft announced 512 GB and 2 TB cards in addition to the 1 TB card [9]. Whether all three are on sale today is unverified. Seagate's own page also lists a card from Western Digital, the WD_BLACK C50, as an expansion card for the same slot [10]. We treat both as examples of the card type, not as a recommendation.
5. Xbox and USB drives: store, but not play. Microsoft says USB 3.1 drives from the Xbox One are plug and play and that you can keep playing Xbox One, Xbox 360 and original Xbox games from them [8]. For games built for the Series X|S, the Xbox Wire text says you can use USB 3.1 storage "to store" them for quick transfer, and its comparison table answers "Plays games optimized for Xbox Series X|S" with "No" for USB 3.1 drives and "Yes" for the expansion card [8]. A Seagate FAQ says the same: external drives can store games but only play legacy titles or transfer files back to internal storage [10]. Our assessment: a USB drive is an archive shelf for Series X|S games. A minimum drive size of 128 GB and a USB 3.0 interface is reported by Tom's Hardware, which also notes that older Xbox One consoles once required 256 GB, and Seagate pages repeat the USB 3.0 point [11][10]. We could not confirm the figures on a Microsoft page that was readable for us, so check the prompt your console shows. The console will offer to format a new drive, which erases it.
6. Steam Deck: a microSD slot and a replaceable SSD module. Valve's tech specs list a "high-speed microSD card slot" with "UHS-I supports SD, SDXC and SDHC" [12][13]. The Steam Deck formats cards itself, using ext4 with casefolding [14]. Games stored on a card appear in your library right away, and the console can boot an operating system from a microSD card [14][15]. The internal SSD sizes depend on the model: Valve's spec sheet for the first generation lists 64 GB eMMC and 256 GB or 512 GB NVMe, and the current spec page lists 512 GB and 1 TB NVMe [12][13]. The spec sheet adds that all models use socketed 2230 M.2 modules, "not intended for end-user replacement" [13]. Valve says parts and repair guides are available through iFixit [14]. Valve does not publish a replacement guide on the pages we could read. The SteamOS recovery page exists at the address in the sources, but its text did not load for us, so we cannot summarise it [16]. Our assessment: treat a drive swap as a repair, not an upgrade. Back up first, read Valve's current terms for your warranty, and note that an SSD swap takes you away from the maker's guidance.
7. Which card for the Steam Deck? Valve specifies UHS-I [12][13]. The SD Association gives 104 MB/s as the top UHS-I bus speed [5], and microSD Express keeps legacy compatibility [6]. Our assessment: a microSD Express card in a UHS-I slot should run in the legacy mode, which would limit it to UHS-I speeds, and the extra cost buys you nothing. We found no Valve statement either way, so this is an inference. A normal UHS-I card is the match Valve names.
8. The same card cannot move between all three. The overview below the steps lists what we read, as of 25 Oct 2026.
9. Models, as examples only. Nintendo says licensed microSD Express cards for the Switch 2 are sold in the Nintendo Store [2], and we found no Nintendo-published list of tested models. For Xbox, the two named cards above are the ones the makers describe for the slot [8][10]. For the Steam Deck, Valve names no card. We rank nothing and name no price. If you compare listings, compare only what the maker's own page states, and note the date of any price you look at.
10. The PS5 is a separate story. It uses a different standard (an internal M.2 slot behind a cover), covered in our PS5 SSD upgrade guide. Our NVMe explainer and our Raspberry Pi 5 storage guide cover M.2 drives in general.
11. Before you buy. Write down the console, the model and the exact standard it names. Ask whether the extra storage needs to run games or only hold them. Then buy the smallest size that solves your actual problem and keep your receipt for the return window.

What each console accepts, at a glance

• Switch 2: microSD Express only, up to 2 TB, no USB drives [1][2][3].
• Xbox Series X|S: Storage Expansion Card in the back slot, or a USB drive for storing games [7][8].
• Steam Deck: UHS-I microSD in the side slot, formatted by the console [12][14].
• A microSD Express card is also accepted by an original Switch, at normal microSD speed [2]. Whether the Steam Deck slot accepts it is not stated by Valve, so treat it as unverified.

A worked example: one household, three consoles

The people and the game sizes here are invented to show the method. Mara owns a Switch 2, an Xbox Series S and a Steam Deck, and all three are full.

• Switch 2: Mara checks the card against Nintendo's rule. Only microSD Express works, and her old microSD cards from the original Switch are useless here, except for importing screenshots [2]. She decides on one card, because Nintendo recommends a single card [1]. She also checks the save data point: saves stay inside, so the card will not rescue a full system memory for saves [3].
• Xbox Series S: she reads that the console has 512 GB or 1 TB internal [7] and sorts her library into two piles: games optimised for the Series X|S and older games. Per the table in Microsoft's Xbox Wire primer, optimised games need the internal SSD or the expansion card to play [8]. Older games can run from a USB drive she already owns, because USB 3.1 drives from the Xbox One work [8]. So she buys nothing: she moves old games to the drive and keeps the new ones inside. If the new pile outgrows the SSD, an expansion card is the only external option the Xbox Wire describes for running them, and she would write down the date and price she saw before buying.
• Steam Deck: she opens Valve's spec page, sees UHS-I, and picks a UHS-I microSD card [12]. She lets the console format it [14]. She does not open the case, because Valve says the SSD module is not intended for user replacement [13].
• Result: one new card, one reused drive, nothing opened. The method matters, the numbers do not: match standard, check what the extra storage can hold, then decide on size.

Checklist

• Name the console model and read the maker's own storage page before you look at a single card.
• Check that the card standard matches: microSD Express for the Switch 2, UHS-I microSD for the Steam Deck, a Storage Expansion Card for playing Series X|S games from outside the console.
• Decide what must live on the extra storage: games to play, games to store, or screenshots only.
• Keep in mind that Switch 2 save data stays in the system memory and use Save Data Cloud where it is available.
• Format the card or drive only through the console's own prompt and back up first, because formatting erases everything.
• Skip USB drives on the Switch 2, and expect them only to store Series X|S games on the Xbox.
• Leave the Steam Deck's SSD alone unless you accept the repair risk, and read Valve's current terms first.
• Compare only manufacturer-stated figures and note the date and source of every price before you pay.
• Insert or remove cards with the console switched off, as Nintendo advises for the original Switch [4].

Related pages: Understanding NVMe SSDs; M.2 form factor and key; PS5 SSD upgrade: specs, heatsink, install; Raspberry Pi 5 storage: SD, USB SSD or NVMe; microSD Express.