With your help, I finally tested this (so far with one game each system, but there should be no reason why the other games don't work as intended now) successfully. But there is a mistake in your posting.

@mitu said in AES/MVS in FBA and Neo Geo system, want two different settings:

modify the system's retroarch.cfg and add core_options_file = `/opt/retropie/configs/<SYSTEM>/retroarch-core-options.cfg`

The emulator does not seem to read from this setting, but there is already an existing setting for this file. Instead of core_options_file look for core_options_path. This worked for me. Anyway, thousands of thanks, as this was the last riddle in the Neo Geo mystery to me and I tried to figure this out since month! I am really happy now.

@matchaman said in Would it be possible to have retropie emulate an actual Neo Geo MVS?:

FBA emulates the Neo Geo flawlessly from what I can tell.

I remember reading fba (actually a fork called fba-rr including recording tools) is the recommended emulator for neogeo speedrun, because of its accuracy.

I understand :/ per game it is then... :)