These are the whole key-point features of the NEOSD:
768 Mbits of flash memory, enough to hold the largest officially released games, plus some extra space for system software.
ARM Cortex M4 at 168MHz, 1MB flash, 128KB RAM. For SD access, Flash programming, cartridge control and original cartridge protections emulation.
2x Lattice XP2 FPGA. Flash based, instant-on, low power, high density FPGAs. For bus decoding and multiplexing, flash access, bank switching, programming help.
Supports micro SD & SDHC cards up to 32GB. FAT32 with long file names.
User friendly game selection menu with game screenshots.
Instant boot to the last flashed game. It appears as an original cartridge to the board, and can use the bios softdips configuration with the original cart.
Runs original games unpatched, emulating the original cartridge protections in hardware.
Ability to boot to the game flash menu from in-game (configurable trigger combination)
Can be used for game development. Allows the homebrew games to access expanded hardware features (S rom banking, increased bank area space).
Updateable system software and firmware for future additions and features.
Switch cartridge region without needing special bios.
MVS board AES emulation without needing special bios.
The NEOSD is fully compatible with all the MAME NEO-GEO RomSet (commercial games). It is also compatible with all the NEO-GEO CD to MVS conversions like Crossed Swords 2, Last Hope or Ironclad. You only need a SD card to copy them.