Geolith vs NeoDS

Geolith is a free emulator for the Neo Geo AES, MVS, CD, and CDZ. It supports commercially released AES, MVS, and CD games, and runs on Linux, macOS, BSD, and Windows. Cartridge systems accept TerraOnion .NEO files; CD systems use .bin/.cue and can optionally use .chd images. BIOS files from a recent MAME set are required, with the needed archives varying by system. Geolith synchronizes its CPUs with the video and sound systems, though video event timing is best effort and cycle-accurate rendering remains a longer-term goal. Settings include system and BIOS mode, region, free play, memory card options, palette, and aspect ratio. Supported inputs range from Neo Geo joysticks to a Mahjong Controller, four-player extension board, V-Liner, and the Irritating Maze trackball. The project was written for The Jolly Good API and can be used in multi-emulator frameworks or standalone binaries. It does not support dedicated JAMMA PCB systems or PAL mode; an early Stakes Winner prototype is also unsupported because required data is missing.

NeoDS is a Nintendo DS emulator for NeoGeo AES and MVS games. It emulates the M68000 and Z80 CPUs, graphics, ADPCM and PSG audio, as well as NeoGeo protection and encryption. NeoDSConvert converts NeoGeo ROM sets into .neo files, and the emulator uses the same ROM sets as MAME. The documented setup requires a Nintendo DS Lite and a DLDI-compatible flash card. A Slot-2 flash card with RAM is optional and can improve the speed of some games. The emulator supports button remapping, normal or scaled video, CPU underclocking, and saving configuration and SRAM to the flash card; its graphical interface is operated with a stylus. It does not emulate FM audio, raster effects or multiplayer, and some timings are not very accurate. The repository describes the project as a fork of a 2008 NeoDS release being updated to 2026 MAME sets. The emulator is free to use for non-commercial purposes; save states appear in the README’s TODO list rather than as a supported feature.