it syncs the components on each cycle (i.e., “cycle-accurate”) while MAME and FBNeo only sync when necessary.
It also has a static ROMset comprised of regular carts that can be scanned via the regular, database scanner instead of needing to do manual scan + DAT.
More specifically, while I understand that cycle-accurate means it’s more faithful to the original hardware, does that translate to MAME/FB NEO not playing the same games as accurately? I mean, will playability and the end user notice actual differences between either, have any tests been taken to compare them?
I don’t know that it matters for any games, or even in any way that’s at all humanly perceivable, but it does make it technically more accurate.
Neo Geo emulation is pretty mature by this point. Even without a cycle-accurate emulator, I still notice no issues, so whatever you pick should be fine. Maybe it shows some difference on extreme edge cases, but I’ve yet to find one.
Long story short, it’s technically more accurate but shouldn’t change anything for the end-user, since the components should be in sync when it matters for all 3 emulators. Visual/audio/gameplay accuracy usually has more to do with how components are emulated than how they are synced.
As a matter of fact (that information might be outdated), around a year ago geolith’s author told me Shock Troopers was actually more faithful to the original hardware in MAME, specifically the way the top of the screen glitches in intro.
Interesting, I always thought NEO GEO emulation was very well done, since the PSP days, even CPS1 and CPS2, I played a lot of these arcades on the handheld and they were pretty much perfect, at least for me.
In counterpart, SNES emulation seemed much more complex in comparison, due to the more modular nature from different carts with special chips and even transparencies, etc., that the more powerful above mentioned arcade boards lacked.
Thank you guys for all the information!
I’d say neogeo emulation might actually be too perfect, original hardware had a few glitches that emulation might not properly reproduce yet. Sometimes there might not even be a will to reproduce those bugs, i remember a user mentioning on FBNeo’s discord that some mslug visual bug from original hardware wasn’t happening in FBNeo, yet when i asked if he wanted us to “fix that” he said no, and i’m pretty sure the “fix” is a one-liner 
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If its really this simple, wouldn’t it make sense to have an option to turn on and off? Well okay with optional fixes its no longer a one-liner.
It definitely would, actually that was my intent to implement this as a dipswitch when i asked if he wanted us to “fix” this, but i gave up on the idea when he said he prefered not having the bug.
In that sense, I agree. If, for preservation sake, someone wants to make a perfect recreation of a certain system, that’s alright, but that shouldn’t be the concern for mainstream emulators; getting things to a point where it’s close enough, while avoiding issues and maintaining playability is what matters the most. Both efforts are valid, but I feel they have different targets.
By the way, wasn’t in FBNeo that there was a bug in CPS3, where there was a very slight color difference on a single screen of a single game, but fixing that would significantly bump hardware requirements? It kinda fits with what we’re talking about.
Oh, and for anyone reading this, do not think I’m complaining about Geolith. It’s a great endeavor and certainly enriches RetroArch. It may simplify the process for users who just want Neo Geo, not everything else that arcade emulations brings along.
Indeed, it was affecting 1 frame on the “vs screen” before battles in sfiii, but we finally managed to fix that without affecting performance.
i like that geolith has mapping options for multi-button-presses (A+B,C+D and so on)
FBNeo has them too, although Geolith has a better choice selection of multi-button for Neo Geo games. Anyway, I remember them being pretty similar.
geolith have b+c , fbneo , no
That’s the only difference? I swore it had more. Anyway, b+c is pretty useful. God knows why it’s a staple in many fighting games of the machine, despite being somewhat weird.
The “only” difference are mainly all the small Things above (unchanging romset, core Options Especially for neogeo, solid scanning/Database Support). Also the Project Bring fresh Air to neogeo Emulation and Surrounding informations.
I meant the multi-button macros.
Sorry for getting it not right first time. My english is terrible.
To be fair, i’m not sure any official neogeo game had a redump for 15+ years, so it should never be a problem with neogeo.
Neogeo romhacks are getting updates though, which brought one question to my mind : are romhacks available as .neo roms ?
i converted a fbneo set with the NeoBuilder Tool found here: https://stoneagegamer.com/neosd-downloads.html
This tool created over 260 .neo roms including some bootleg, hacks and prototypes. Sadly the RA Scanner created Playlist is missing around 10 games (f.e. Sengoku 3) but thats not very far from perfect