How much microSD storage does your Pocket Duo need?

Typical game file sizes

Average game sizes as described by the No-Intro and Redump catalogues (updated November 2, 2026).

Cartridge games are tiny, so a full Game Boy or Super Nintendo library fits in a few gigabytes, and disc games are where the space goes. Each disc of a multi-disc game is its own file. These averages cover every region and revision, so your own collection may come out a little bigger or smaller.

Switch games vary the most. Standard digital NSP files average 1.3 GB, while full XCI cartridge files average 6.2 GB, and updates, DLC and a few very large games can push a Switch library well past either figure.

Compressing your games can save a lot of space. Dolphin says uncompressed GameCube and Wii games are about 1.4 GB and 4.7 GB and recommends its RVZ format, which shrinks them by an amount that depends on the game. CHD does the same for many disc systems, but not every emulator can open it. If you already have your games, their real sizes beat any average.

Original Xbox games are a special case. HakuX, the Xbox emulator for Android, plays ISO or XISO files. A full Xbox disc image carries a video section as well as the game, and an XISO keeps only the game part, so it’s usually much smaller. Retro Game Corps found most 7.39 GB images shrink to about 3 GB, so treat the Xbox figure above as the most you’d need. Skip CHD and CCI for Xbox: xemu doesn’t open CHD, and CCI is made for Cerbios, with no word yet that HakuX supports it.

The Xbox 360 figure tells you how much room the games take, not whether they’ll run. XenDroid asks for an Adreno 740 or newer and hasn’t been tested on lower chips, including the Duo’s Adreno 722.

What belongs on the card?

The Duo has 128 GB of built-in storage and a microSD (TF) card slot. Put your games, artwork and music on the card, and keep Android and the emulator apps in built-in storage, which is where Android puts apps anyway. Each emulator or frontend asks you to pick its game folder the first time you open it.

Leave about 20% of the card free for new games, saves, updates and artwork. For folders and first setup, see the Pocket Duo quick start.

Which card to buy

Buy a name brand from a seller you trust. SanDisk and Samsung are the cards Retroid owners mention most, and owners also report good results with Lexar, Kingston, PNY, TeamGroup and Patriot. No Duo owner has reported a card that failed, so stick with a well-known brand.

Fake cards are the bigger risk. Several people in the Duo community have bought one, including a “1 TB” card that held 8 GB and a “256 GB” card that held 64 GB. Fakes usually come from marketplace sellers and look like a bargain, so be suspicious of any card priced well below the table below. Before you copy games onto a new card, check its real size with F3 on a Mac or Linux, or H2testw on Windows.

Look for U3 and A2 on the label. A1 cards load games fine, but owners say frontends like ES-DE start noticeably slower when their artwork sits on an A1 card. Skip microSD Express cards, which are made for the Switch 2: they cost more and run at ordinary speed in a regular slot.

Format the card as exFAT. The Duo’s storage settings will format it for you, or choose exFAT if you format it on a computer. FAT32 can’t hold a file bigger than 4 GB, which rules out most GameCube, Wii and PS2 games.

These are rough US prices for name-brand cards, checked November 4, 2026. Flash memory prices rose sharply through 2026, with some 512 GB cards doubling in a few months, so expect them to move.

Retroid hasn’t said what the largest supported card is, and no Duo owner has confirmed a 1 TB or 2 TB card yet. One Pocket 6 owner runs a 2 TB card, which is a good sign but not a guarantee, so check with Retroid before buying a very large one. Card makers count 1 GB as 1,000 MB, so Android will always show a bit less free space than the label says.

For setup by system, see the DS and 3DS guide or the frontend guide.