Supported memory cards:

• SD: 512MB, 1GB, 2GB
• SDHC: 4GB, 8GB, 16GB, 32GB

Other cards might work (SD smaller than 512MB and SDHC bigger than 32GB) but were not tested and are generally not recommended.
IMPORTANT: 4GB SD cards are NOT supported. Neither are SDXC cards of any kind.

SD cards come in various speed grades called classes. Usually class 4 cards offer good enough performance and there is little need for anything faster. Even class 2 might work well, you’ll have to try and see.
In fact speed class only tells you how fast the card is during streaming, not what the random access latency is. It’s possible for a good class 4 card to outperform a medicore class 10.

IMPORTANT: There are many brands available, and worse yet, a lot of counterfeits. Some cards appear to be more stable than others so if you get any weird issues like GDEMU failing to detect the card sometimes, or random hangs after a few hours of play, try a different brand/size card.
In general it’s better to stick to 2-8GB cards from well known manufacturers, and if you’re using a size adapter make sure it’s a quality one.

NOTE: Do not use Transcend Class 10 cards, these cause problems.

Supported filesystems:

• FAT (also known as FAT16)
• FAT32

IMPORTANT: exFAT is not supported.

Card preparation guidelines:

• Cards up to 2GB should be formatted with FAT16
• Cards bigger than 2GB should be formatted with FAT32
• Use the biggest cluster size available (32kB in most cases, 64kB clusters are also supported)
• DOS partition table is supported but only first partiton will be used
• For best results use software called SD Formatter

SD Formatter can be obtained free of charge.