If you back up Switch save data regularly, your microSD card does more work than most people expect. Every JKSV backup writes to it, and many players also keep an emuMMC partition, screenshots, and their game library on the same card. Choosing well is less about chasing the fastest specification and more about matching capacity, consistency, and durability to how you play. If you have not installed the tool yet, start on our page to download JKSV, then come back before you buy.
Start With Capacity, Not Speed
Save data itself is small. Most individual game saves are measured in megabytes, and even a complete set of JKSV backups for a large library usually stays modest. What consumes space is everything around those backups: an emuMMC copy of the system memory, installed games and updates, screenshots and video captures, and the safety margin you need so the card never fills up mid-backup. A nearly full card is a slow and risky card, so buy for the total picture, not just for saves.
- 128GB: Enough for save backups, homebrew files, and a modest digital library. This tier suits players who mostly buy physical game cards and only need a reliable home for backups.
- 256GB: The balanced tier for most owners. It leaves comfortable room for an emuMMC partition alongside backups and a growing digital library, without paying for space you may never use.
- 512GB: Better for players with a large digital collection, several user profiles worth of backups, or an emuMMC plus room to keep multiple generations of save archives instead of deleting old ones.
- 1TB: A specialist tier for very large libraries and long-term archives. Only choose it if you already know your 512GB card fills up; for backup use alone it is rarely necessary.
Keeping older backups matters: last month’s copy can be the only clean one if a save corrupts today, so headroom for several dated copies is a safety feature, not wasted space.
The Speed Labels That Actually Matter
The Nintendo Switch 1 card reader is a UHS-I interface, so that is the standard your card needs to meet well. Cards rated above UHS-I do not run faster in the console; they simply fall back to UHS-I speeds. Within UHS-I, look at three markings. The UHS Speed Class, shown as a number inside a U, tells you the minimum sustained write speed, and U3 is the comfortable choice for frequent backup writes. The Video Speed Class, such as V30, states a similar sustained-write guarantee in different language. The Application Performance Class, A1 or A2, describes random read and write performance, which affects how snappy small-file operations feel. A2 is the newer and stronger rating, but a genuine A1 card from a reputable maker still performs perfectly well for save backups.
Consistency beats peak numbers: a card that writes steadily finishes a backup session predictably, while a bargain card can stall on the small files that make up save data.
Endurance: The Overlooked Specification
Backups are write-heavy work. If you back up after every session or keep emuMMC data on the card, consider a high-endurance line, built and warranted for sustained writing like dash-camera cards. For occasional backups a standard card from a reputable brand is fine; for daily routines, endurance decides how many years the card lasts.
How to Avoid Counterfeit Cards
Fake capacity cards are the single biggest risk in this market. A counterfeit may report 512GB while holding far less, and it typically fails exactly when it fills past its real capacity — which can mean silently losing the backup archive you trusted it with. Protect yourself with a few simple habits:
- Buy only from established retailers or a brand’s official storefront, never from an anonymous listing at a price far below every other seller.
- Test a new card on a computer before trusting it: fill it beyond the size of your current data, or run a free capacity-verification utility, and confirm files still open.
- Keep the receipt and packaging until the card has survived a few full backup cycles.
- Copy important archives to a second location, such as the cloud setup described in our guide to the best cloud storage for JKSV WebDAV backups.
Where to Buy
Use the retailer links below to compare current capacity tiers and endurance lines. Both are affiliate links — the retailers pay us a small commission if you buy, at no extra cost to you, and the links currently point to each retailer’s homepage while our affiliate accounts are being finalized. Search there for UHS-I, A1 or A2, U3 or V30 cards in the capacity tier you chose above.
Still deciding on the supporting gear? Our companion guide to the best card readers and USB accessories explains how to move backups to a PC quickly, and our explainer on microSD Express and Switch 2 explains why the newer, pricier Express cards are not the right purchase for a Switch 1. Once your card is installed and tested, make your first full backup the same day — an untested backup routine is only a plan.
This page contains affiliate links. If you buy through them, we may earn a commission at no extra cost to you. See our Affiliate Disclosure.