express train to storageville Explaining MicroSD Express cards and why you should care about them Little-used 2019 standard bridges a gap between internal and external storage. Andrew Cunningham Apr 3, 2025 10:00 am | 9 The microSD Express standard has existed for a long time, but it hasn't seen wide adoption in a mass-market consumer device. Enter Nintendo's new Switch 2. Credit: SanDisk The microSD Express standard has existed for a long time, but it hasn't seen wide adoption in a mass-market consumer device. Enter Nintendo's new Switch 2. Credit: SanDisk Story textSizeSmallStandardLargeWidth *StandardWideLinksStandardOrange* Subscribers only Learn moreAmong the changes mentioned in yesterday's Nintendo Switch 2 presentation was a note that the new console doesn't just support MicroSD Express cards for augmenting the device's 256GB of internal storage, but it requiresMicroSD Express. Whatever plentiful, cheap microSD card you're using in your current Switch, including Sandisk's Nintendo-branded ones, can't migrate over to your Switch 2 alongside all your Switch 1 games.MicroSD Express, explainedWhy is regular-old MicroSD no longer good enough? It all comes down to speed.Most run-of-the-mill SD and microSD cards you can buy today are using some version of the Ultra High Speed (UHS) standard. Designed to augment the default speed (12.5MB/s) and high speed (25MB/s) from the earliest versions of the SD card standard, the three UHS versions enable data transfers of up to 624MB/s.But most commodity microSD cards, including pricier models like Samsung's Pro Ultimate series, use UHS-I, which has a maximum data transfer speed of 104MB/s. The original Switch uses a UHS-I microSD card slot for storage expansion.Why have newer and faster versions of the standardUHS-II, UHS-III, and SD Expressfailed to achieve critical mass? Because for most consumer applications, it turns out that 100-ish megabytes per second is plenty. The SD Association itself says that 90MB per second is good enough to record an 8K video stream at up to 120 frames per second. Recording pictures and video is the most demanding thing most SD cards are called upon to dogive or take a Raspberry Pi-based computerand you don't need to overspend to get extra speed you're not going to use.All of that said, thereis a small but measurable increase in launch and loading times when loading games from the original Switch's microSD card instead of from internal storage. And for games with chronic performance issues like Pokmon ScarletandViolet, one of the community-suggested fixes was to move the game from your microSD card to your Switch's internal storageto alleviate one of the system's plentiful performance bottlenecks.The Switch 2's additional power opens the door to more complex games that could lag even more noticeably, especially if they're ported from consoles that expect more than 50 times the storage bandwidth (Sony requires an SSD with read speeds of at least 5,500MB/s for the PlayStation 5).And that's where SD Express comes in. These cards are connected to the same PCI Express/NVMe interface that internal SSDs use in modern PCs and the other game consoles, theoretically giving your SD card access to the same bandwidth as internal storage.Now, you won't actuallyget performance as fast as an internal SSD using this interface. The speed varies a lot based on the PCI Express version your gadget is using (3.0 or 4.0) and how many "lanes" of bandwidth it's allowed to use (these are, in short, the connections between a device's CPU and external accessories like SSDs, Wi-Fi adapters, or dedicated GPUs, and all CPUs and SoCs have a limited number of them to hand out). Depending on these factors, microSD Express can deliver anywhere between 985MB/s and 3940MB/s of theoretical bandwidth.MicroSD cards will also be slowed down because there are fewer physical flash memory chips to write to at a time, a process called "interleaving" that is responsible for much of an SSD's speed. This SanDisk microSD Express card, one of the only ones actually available at retail right now, lists its top speeds as 880MB/s for reads and 650MB/s for writes.But even at its worst, this is several times the amount of bandwidth available to whatever UHS-I microSD card is inserted into your current Switch. Express cards won't make an SD card feel as fast as internal storage, but it will help the microSD card keep pace a bit.At what cost?One other benefit of workaday, plain-old UHS-I microSD cards? The price. Great ones are cheap. Good-enough ones are dirt cheap, even if you stick to major storage vendors like Samsung, Sandisk, and Lexar (please do not buy no-name solid state storage). A quality 256GB microSD card will run you around $20, a pittance compared to whatever you paid for the device you're putting it in.For the SanDisk microSD Express, the same amount of storage will run you around $60. This is not only more expensive than a regular cheap SD card, but it's more expensive than actual internal SSDs. The cheaper name-brand 1TB internal SSDs, including some sold by SanDisk parent company Western Digital, can give you four times as much space for around the same price.These prices should go down over time, and the Switch 2 will be a part of the reason whyat a bare minimum, it will likely prompt the creation of multiple alternate microSD Express options from SanDisk's competitors. But at launch, it may still feel like a raw deal because it's just one ofmany things about the Switch 2 that costs more money than the Switch 1. Compared to the first Switch, you're paying between $100 and $150 more for the console itself, $10 more for each pair of Joy-Cons or Pro Controllers you buy, $50 for a replacement dock, and between $10 and $20 more for first-party games.The Switch 2's relatively generous 256GB of internal storage should help you avoid the need for an SD card, and it could be all you ever need if you manage your storage space carefully. But the extra cost of microSD Express on top of everything else does rankle, even if the technical reasons behind the move are totally justifiable.Andrew CunninghamSenior Technology ReporterAndrew CunninghamSenior Technology Reporter Andrew is a Senior Technology Reporter at Ars Technica, with a focus on consumer tech including computer hardware and in-depth reviews of operating systems like Windows and macOS. Andrew lives in Philadelphia and co-hosts a weekly book podcast called Overdue. 9 Comments