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Geolith
What it is
Geolith is a free emulator for Neo Geo AES, MVS, CD, and CDZ systems, with builds for Linux, macOS, BSD, and Windows. Its project documentation states compatibility with commercially released AES, MVS, and CD games. Cartridge systems accept TerraOnion .NEO files, while CD systems use .bin/.cue files and can optionally use .chd images. BIOS files from a recent MAME set are required, with the needed archives varying by system. Settings cover system and BIOS mode, region, free play, memory cards, palette, and aspect ratio. Supported inputs include Neo Geo joysticks, a Mahjong Controller, a four-player extension board, V-Liner, and the Irritating Maze trackball. Geolith synchronizes its CPUs with video and sound components, but video event timing is best effort, and cycle-accurate rendering remains a longer-term goal. The project says games are playable with minor differences from real hardware and no known major bugs. It does not support dedicated JAMMA PCB systems or PAL mode, and an early Stakes Winner prototype cannot yet be emulated because data is missing. Geolith was written for The Jolly Good API and can run in multi-emulator frameworks or as a standalone binary.
For and against
For
- Free to use.
- Supports AES, MVS, CD, and CDZ systems.
- Works with Linux, macOS, BSD, and Windows.
- Supports multiple specialized controllers.
- Can run standalone or in multi-emulator frameworks.
Against
- Requires BIOS files from a recent MAME set.
- No dedicated JAMMA PCB or PAL mode support.
- An early Stakes Winner prototype cannot yet be emulated.
- Video event timing is best effort.
The verdict
Geolith supports a broad range of Neo Geo systems and inputs, with stated compatibility for commercially released AES, MVS, and CD games. Check the BIOS and file-format requirements, and note its listed system and timing limits.
Who it suits
Geolith suits players and preservation-minded users seeking to emulate Neo Geo AES, MVS, or CD games on a supported desktop operating system. Users will need the appropriate BIOS files and game files in supported formats.
On the record
- Accuracy
- The emulator synchronizes its CPUs with video and sound components, while video event timing is described as best effort and cycle-accurate rendering remains a longer-term goal.gitlab.com · read 29 Sep 2026
- Accuracy caveat
- Video events use best-effort timing; the project says games are playable with minor differences from real hardware and no known major bugs.gitlab.com · read 30 Sep 2026
- API integration
- Geolith is written for The Jolly Good API and requires that API's header files to compile.gitlab.com · read 29 Sep 2026
- BIOS requirement
- BIOS files from a recent MAME set are required.gitlab.com · read 30 Sep 2026
- Build platforms
- The README gives build instructions for Linux, macOS, BSD, and Windows using MSYS2.gitlab.com · read 30 Sep 2026
- Cartridge format
- Cartridge systems support TerraOnion’s .NEO file format only.gitlab.com · read 30 Sep 2026
- Compatibility
- The project states that Geolith is compatible with 100% of commercially released Neo Geo AES, MVS, and CD libraries.gitlab.com · read 30 Sep 2026
- Disc formats
- CD systems support .bin/.cue and, optionally, .chd disc images.gitlab.com · read 30 Sep 2026
- Emulation detail
- The CPUs are emulated at instruction-level granularity and synchronized with each other, the LSPC video system, and YM2610 sound.gitlab.com · read 30 Sep 2026
- Framework
- Geolith was written for The Jolly Good API and can also be used in multi-emulator frameworks or standalone binaries.gitlab.com · read 30 Sep 2026
- Game formats
- Cartridge systems support TerraOnion .NEO files, while CD systems support .bin/.cue and optionally .chd disc images.gitlab.com · read 29 Sep 2026
- Input devices
- Supported input devices include Neo Geo joysticks, the Mahjong controller, a four-player extension board, V-Liner, and the Irritating Maze trackball.gitlab.com · read 30 Sep 2026
- Known limits
- Dedicated JAMMA PCB systems and PAL mode are not supported, and an early Stakes Winner prototype cannot currently be emulated due to missing data.gitlab.com · read 29 Sep 2026
- Latest changelog entry
- Version 0.4.2 lists a fix for an LSPC state leak when switching between CD and cartridge games and support for The Jolly Good API 2.0.0.gitlab.com · read 29 Sep 2026
- License
- The README identifies Geolith as BSD-3-Clause licensed.gitlab.com · read 30 Sep 2026
- Maintainer
- The README credits Rupert Carmichael with Geolith copyright from 2022 through 2026.gitlab.com · read 29 Sep 2026
- Maker
- The README credits Rupert Carmichael and Romain Tisserand for Geolith copyright.gitlab.com · read 30 Sep 2026
- Notable limits
- Dedicated JAMMA PCB systems and PAL mode are not currently supported, and an early Stakes Winner prototype cannot yet be emulated.gitlab.com · read 30 Sep 2026