microSD for Switch 2 and Steam Deck: The Rules Changed

The rules split in 2025: the Nintendo Switch 2 accepts only microSD Express cards for game storage — every microSD card you already own is locked out — while the original Switch and the Steam Deck still use ordinary UHS-I microSD, where paying for a faster card past ~100MB/s buys you nothing. Same-looking little cards, three different right answers.

Here is which card actually fits which machine, what the logos on the package mean, and where the marketing numbers quietly stop applying.

Which microSD card works in which handheld

The rest of this guide unpacks each row, because the differences are bigger than they look — one of them makes a card useless, and two of them just make it a bad deal.

Switch 2: microSD Express or nothing

Nintendo’s official compatibility page leaves no wiggle room: the Switch 2 uses microSD Express cards only for saving and downloading games, supports them up to 2TB, and conventional microSD cards cannot be used for game storage. The one carve-out is read-only nostalgia: if you had screenshots and videos on a regular microSD card in an original Switch, the Switch 2 can read those off the old card. That is the entire extent of backward compatibility.

How to tell the cards apart at a glance: a microSD Express card carries two logos — the standard microSD mark plus an “EX” logo. If the EX logo is missing from the product photos, the card is the old standard, no matter what the listing title says about the Switch. Nintendo also notes that the first time you use a microSD Express card, the console needs an internet connection and a system update.

Why the hard cutoff? Speed. Regular microSD tops out at the UHS-I bus limit of 104MB/s. microSD Express moves the card onto a PCIe/NVMe interface — the same family of technology as the SSDs we compared in our NVMe enclosure speed guide — and the Switch 2-class cards quote sequential reads around 800MB/s. Nintendo built the console’s game-loading assumptions on that, so slower cards were cut entirely rather than allowed to degrade the experience.

What that means at the register, using manufacturer launch pricing:

• Samsung P9 Express 256GB (Switch 2 licensed, Mario edition sold too) — launched at $54.99, quotes up to 800MB/s reads, and has repeatedly discounted into the low-$30s, which is the best cost-per-GB in the Express category at the time of writing.
• SanDisk microSD Express for Nintendo Switch 2 (officially licensed) — the other big-brand option, with retail listings quoting reads up to 880MB/s and writes up to 650MB/s; the 256GB card typically sells around the $70 mark at the time of writing.
• 512GB Express cards — roughly double the money (Samsung’s launched at $99.99).

Check the Samsung P9 Express for Switch 2 on Amazon

Check the SanDisk microSD Express for Switch 2 on Amazon

One more asymmetry worth knowing: Express cards work in old UHS-I devices, but only at UHS-I speed. Nintendo confirms a microSD Express card functions in the original Switch — at ordinary microSD performance. So an Express card is a defensible buy if you own an original Switch today and know a Switch 2 is coming; it is a poor buy for any device that will never leave the UHS-I world.

Original Switch: the cheap answer is the right answer

The original Switch (and Switch Lite / OLED) accepts microSD, microSDHC and microSDXC up to 2TB over UHS-I. Nintendo’s own FAQ recommends a UHS-I card with a 60–95MB/s transfer speed, adding that higher transfer speeds give a better gameplay experience — and that range is telling, because 95MB/s is essentially the UHS-I ceiling. In other words, Nintendo is saying: buy a decent mainstream UHS-I card, and you are done.

That makes the original Switch the easiest storage purchase in gaming right now. A SanDisk Ultra or Extreme in 256GB — both sold with explicit “Nintendo Switch verified” branding — lands in the $20–35 range at typical street prices, and the Extreme’s V30/A2 ratings give it a second life in a camera, drone or Steam Deck later. What you should not do is pay extra for headline reads of 160MB/s or more: those numbers require the maker’s proprietary reader, and the Switch’s UHS-I slot will never see them.

Check Switch-verified SanDisk microSD cards on Amazon

Steam Deck: the slot is UHS-I, so buy IOPS, not MB/s

Valve’s official tech specs describe the Steam Deck’s card slot in one line: “UHS-I supports SD, SDXC and SDHC.” That single line settles most of the buying decision, because the UHS-I bus tops out at 104MB/s — every UHS-I card on the market, from the cheapest to the most premium, converges on roughly the same sequential ceiling inside a Deck.

So the differentiator moves to the numbers most people skip: the Application Performance Class. By SD Association specification:

• A1 guarantees 1,500 random-read and 500 random-write IOPS
• A2 guarantees 4,000 random-read and 2,000 random-write IOPS (with host support for features like command queuing)

Loading a game is not one big sequential read — it is thousands of small, scattered reads. That is precisely the workload the A-class measures. Combined with V30 (a guaranteed minimum of 30MB/s sustained writes, which is what matters when you install or shuffle games onto the card), the shopping spec for a Steam Deck card is short: UHS-I, U3/V30, A2, from a brand you trust. The SanDisk Extreme line and Samsung’s equivalent tiers check every box; capacity is then purely a budget call, and since the Deck treats the card as a live game library rather than an archive, bigger is genuinely better.

Check A2-rated SanDisk Extreme cards on Amazon

Check A2-rated Samsung microSD cards on Amazon

Two things not to do for a Deck. Don’t buy a microSD Express card — even where it works, the UHS-I slot reduces it to an expensive ordinary card. And don’t chase 190MB/s or 210MB/s headline reads for the same reason. If you actually need faster Steam Deck storage, the answer isn’t a better card — it’s playing docked from external storage, which we covered in our Steam Deck dock guide.

How to read a microSD label in ten seconds

The front of a card is a soup of logos, but only a few carry guarantees:

The pattern to internalize: big printed MB/s numbers describe reads in ideal conditions; the small class logos are the actual contracts. It is the same lesson as USB cables, where the printed generation name tells you less than the certified wattage and data logos — a theme we’ve covered in USB-C cables, explained.

Who should buy what

Switch 2 owner: a 256GB licensed microSD Express card — Samsung P9 Express or the SanDisk licensed card. Check for the EX logo, expect $55 list and real-world sales well under it. Nothing else works.

Original Switch owner, no Switch 2 plans: a Switch-verified UHS-I card (SanDisk Ultra/Extreme class), 256GB, in Nintendo’s recommended 60–95MB/s band. Cheapest correct purchase on this page.

Original Switch owner, Switch 2 incoming: consider buying the microSD Express card now — it runs (slowly) in the old console and moves to the new one at full speed.

Steam Deck owner: UHS-I, V30, A2, as much capacity as the budget allows. Ignore every MB/s figure above 104 — Valve’s slot can’t use it.

And whichever machine you’re buying for: get the card from a first-party or official-store listing and test it when it arrives. Capacity-faked cards remain a real problem in this category, and a handheld that suddenly can’t read its library is the worst way to find out.

More storage and handheld guides are on gadget-hub.jp English.