The microSD card is the most underrated component of a retro handheld console, yet it is the one that causes the most failures. By the end of this guide, you will be able to decode speed classes, understand what the A1 and A2 labels mean, choose a capacity that matches the systems you play, decide between FAT32 and exFAT, spot a counterfeit and check a card before trusting it with your saves.
What you need
- A reliable microSD card reader, preferably USB 3.
- A computer running Windows, macOS or Linux.
- A utility to test real capacity and a utility to measure transfer speeds.
- Your console's product page, to know the maximum supported capacity.
Step 1: decode the markings printed on the card
A microSD card displays half a dozen symbols, and most of them have nothing to do with the use we care about. Here is how to rank them.
Sequential speed classes
The number inside a U (U1, U3) and the V rating (V10, V30, V60) indicate the minimum guaranteed sustained write speed. These values were designed for video. For a retro console, they mainly matter when you copy your files. In game, their influence is marginal.
The A1 and A2 classes, the ones that really matter
The A1 or A2 label refers to random access performance, meaning the ability to read a multitude of small scattered fragments. That is exactly what an emulator does when it loads textures, reads through a disc image or displays a list of several thousand entries with their box art. A1 guarantees 1,500 read operations per second, A2 guarantees 4,000.
In practice, A1 is the right baseline for a retro handheld console. A2 brings a gain on recent Android devices, but depends on hardware support that is not universal. An A2 card in a device that does not use it behaves like an A1.
What is useless
Marketing labels such as “4K optimised” say nothing about random access. A card sold for video can show an excellent V30 rating and crawl on small files.
Step 2: choose the right capacity
There is no point going for the maximum by reflex. The useful capacity depends on the systems you play, because game sizes vary enormously from one generation to the next.
- 8- and 16-bit systems (monochrome handhelds, home consoles of the era): files weigh from a few kilobytes to a few megabytes. A low-capacity card is more than enough for hundreds of titles.
- 32-bit systems and more recent handhelds: you move up to a few tens or hundreds of megabytes per game. A medium-capacity card becomes comfortable.
- Optical-media systems and 3D consoles: each game can weigh several gigabytes. This is where large capacities really make sense.
Two limits should guide your choice. First, the maximum capacity supported by your console, which varies between models: check the product page or ask our customer service. Second, common sense: a very large card concentrates all your risk on a single medium. Two medium-sized cards are often better than one huge one.
Step 3: FAT32 or exFAT, how to decide
The file system determines how data is organised on the card. Two formats dominate, and the choice is not trivial.
FAT32
Maximum compatibility. This is the format most reliably recognised by retro console interfaces, particularly devices running embedded Linux. Its main limitation: no individual file can exceed 4 GB. For the vast majority of retro systems, you will never hit this limit. It becomes a problem as soon as you handle large disc images.
exFAT
No file size limit in practice, and more flexible handling of very large capacities. On the other hand, exFAT is less universally supported by retro interfaces and is more sensitive to sudden power-offs.
The simple rule: keep the original format of the card supplied with the console. If you are preparing a new card, prefer FAT32 for older systems, and exFAT only if you need files larger than 4 GB and your device supports it. Depending on the model, some consoles use several partitions: reformatting the system card then erases the firmware. Never do it without a full backup.
Formatting works differently on Windows, macOS and Linux, and a large-capacity card needs a dedicated utility to stay in FAT32. We cover each case in our guide to formatting a microSD card in FAT32 or exFAT.
Step 4: spot a counterfeit and test the card
Fake microSD cards are a plague of the grey market. The principle is always the same: a low-capacity chip is reprogrammed to report a fictitious capacity. The card accepts files without complaint, then silently overwrites data once the real capacity is reached. You discover the problem when you notice that half of your games and saves are corrupted.
Warning signs when buying
- A price far below the market for a large capacity.
- Sloppy packaging, blurry printing, a misaligned logo.
- A third-party seller with no history on a marketplace.
- An advertised capacity that does not exist in the manufacturer's official range.
Test every new card, systematically
- Insert the card into a reader connected to the computer.
- Run a real-capacity verification utility, which writes data across the whole volume and then reads it back to compare.
- Let the test run to completion: for a large capacity, allow several hours.
- Check that the validated capacity matches the advertised capacity, allowing for the conversion margin.
- Then measure read and write speeds with a performance-testing utility.
This test only costs machine time. Do it before copying anything, since it erases the contents of the volume.
We go through this procedure step by step, with the utilities to use and how to read the results, in our article on how to check that a microSD card is not counterfeit.
Common mistakes
- Choosing capacity over speed. A large card without an A1 rating will make your menus sluggish and your loading times long. For the same budget, a more modest capacity with A1 or A2 offers a much better experience.
- Reformatting the original card without a backup. On many models, this card contains the system. One quick format and the console no longer boots. Always make a full copy of the contents on your computer before doing anything.
- Using exFAT on a device that does not support it. The console then simply ignores the card, or shows no games. Switch back to FAT32 if in doubt.
- Removing the card without ejecting it properly. This is the leading cause of corruption. Always eject through the operating system, and switch the console off completely before removing the card.
- Trusting a card found in a drawer. An old card may have worn out its cells and keep accepting writes while losing data. Test it before trusting it with your saves.
The card is also one of the most common causes of crashes: before suspecting the emulator, go through the fourteen possible causes of a game that won't launch.
Frequently asked questions
Is an A2 card really faster than an A1 in game?
It depends on the device. A2 relies on a caching mechanism that not all controllers use. On a retro console running embedded Linux, the gain is often zero. On a recent Android device loading large systems, it becomes noticeable. When in doubt, A1 remains the safe choice.
Do you need a branded card?
Yes, and above all one bought from an identified retailer. The major brands supply components with the advertised specifications and a usable warranty. The main risk does not come from the brand but from the distribution channel, where counterfeits with perfectly imitated logos circulate.
Can I use two cards in the same console?
Depending on the model, some devices have two slots, one reserved for the system, the other for games. It is a comfortable setup: the system stays intact and you can swap the games card freely. Check your console's product page or contact our customer service to find out the exact configuration of your model.
How long does a microSD card last?
There is no universal answer. Flash memory wears out with writes and a card can stop working without warning. The only real protection is to copy your saves to a computer regularly.
Going further
Once the card is chosen and tested, move on to filling it with How to add games to a retro handheld console, then keep your progress safe with Saves: never lose your progress. If you are thinking of changing interface, first read Alternative firmware: should you install one?
Our SanDisk cards by use
- Linux-based retro console (Anbernic, Miyoo, TrimUI): SanDisk Ultra 256 GB, the capacity that is enough for most game libraries.
- Android console that launches its apps from the card: the A2 rating of the SanDisk Extreme PRO 512 GB or the SanDisk Extreme 1 TB or 2 TB.
- Large PS2 or GameCube library: SanDisk Ultra 1 TB or 1.5 TB, provided the console accepts these capacities.
- ROG Xbox Ally and Ally X: the SanDisk card designed for them, in 1 TB or 2 TB.
Discover our selection of microSD cards, our Anbernic consoles and our handheld consoles.