A new kind of memory card is appearing in shops, and it is causing real confusion. microSD Express cards cost noticeably more than regular microSD cards, carry different logos, and are marketed alongside the Nintendo Switch 2. If you use JKSV to back up save data, the short answer is simple: JKSV runs only on the original Nintendo Switch, and that console does not need — and cannot benefit from — a microSD Express card. This page explains the difference so you do not pay for the wrong card. For the tool itself, see our page to download JKSV.
What microSD Express Actually Is
Regular microSD cards communicate through the UHS interface. microSD Express changes the connection itself, adding a PCIe lane and using the NVMe protocol — the same basic technology family as fast computer SSDs. In a device built for it, that allows much higher transfer speeds than UHS-I can reach. Express cards carry the SD Express markings and new speed grade symbols, and they are physically the same size and shape as the microSD cards you already know, which is exactly why the two types are so easy to mix up at checkout.
Because the shape is identical, an Express card can generally work in an older device in a slower compatibility mode. The reverse is the important direction: a device that requires Express performance will not get that performance from a regular card, no matter how good the regular card is.
Why the Switch 2 Uses Express Cards
The Nintendo Switch 2 was designed around faster storage. Its internal storage is quicker, its games can stream data at higher rates, and Nintendo specified microSD Express for expandable storage on that console so the card would not become the bottleneck. In practical terms, if you own a Switch 2 and want to expand its game storage, a microSD Express card is the correct purchase, and a regular UHS-I card is not a substitute for that job even if a fast one tempts you on price.
Why the Switch 1 — and JKSV — Do Not Need It
The original Switch has a UHS-I card reader. Any card you insert, Express or not, is limited by that reader. An Express card in a Switch 1 gives you no speed advantage for loading games, and it gives JKSV no advantage either: backing up save data involves many small files and finishes quickly on any genuine UHS-I card that meets the standards in our guide to the best microSD cards for Switch save backups.
Be equally clear about the software side. As of the date of this guide, JKSV is a Nintendo Switch 1 application that runs under Atmosphère on that console. There is no JKSV version for the Switch 2, so buying an Express card does not prepare your Switch 2 for JKSV, and it does not move your Switch 1 saves anywhere by itself. If a listing suggests otherwise, treat it as marketing confusion, not a feature.
How to Tell the Two Apart When Shopping
- Check the card face and packaging for the words microSD Express or the EX-related speed markings; regular cards instead emphasize UHS-I, A1 or A2, and U3 or V30.
- Check which console the listing names. Cards sold for Switch 2 storage expansion should say Express; cards for the original Switch should be UHS-I.
- Be suspicious of price. A very cheap card claiming Express performance is a red flag for counterfeits, just as it is with regular cards.
- Match the card to the device in front of you, not the device you might buy later. Card prices and capacities change quickly, so there is little reward for stockpiling.
So Which Card Should You Buy?
Own only a Switch 1 and use JKSV? Buy a genuine UHS-I card using the capacity tiers in our microSD buying guide, and pair it with a decent reader from our guide to the best card readers and USB accessories for moving archives to a PC. Own a Switch 2 as well? Keep the cards separate in your mind and in your drawer: Express for the Switch 2 game library, UHS-I for the Switch 1 where your JKSV backups live. Own only a Switch 2? An Express card is the right expansion purchase, but understand it is for game storage — your save backup options on that console are the official ones, not JKSV.
That separation is the whole lesson. The more expensive card is not the better card in the abstract; it is only better in the console designed for it. Buy for the reader your data actually passes through, and your backups will be just as safe for less money.
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