Here is a breakdown of what you need to know to get it working correctly. 1. Match the Romset Version MAME 0.139u1 corresponds exactly to the MAME 2010 romset The Problem:
If you experience low frame rates (common with Metal Slug 6 on older MAME versions), many users recommend: RetroArch Flycast Core metal slug 6 mame 0.139u1 rom
The file size was around 80 MB – tiny by today’s standards, but huge compared to Neo Geo ROMs. It required the ( awbios.zip ) placed in the roms folder as well. Here is a breakdown of what you need