He is on a naoimi cab so the max resolution is 640x480. If using batocera edit the file boot/batocera-boot.conf to force a maximum resolution by editing the following line:
es.resolution=max-640x480
To be honest old 15k jamma games look bad stretched to 640x480. Best to at least try the "ati card" and install the emudriver software for the card and then groovymame. It will output a "super resolution" for your capcom fighters at 2560x448p.
The 2560 horizontal res means silky smooth perfect scrolling and the 448p vertical is exactly 2x the resolution of the original 15k monitors in jamma cabs. Once you turn on mame scanlines it looks *exactly* like an original jamma 15k monitor.
This is covered at the end of the video above.
If you don't have the time to learn about pc configuration and settings, possibly chunksins groovytime image would be good to look at. I just don't know if it supports 31k naomi monitors as I only tested it on the older jamma 15k ones:
I've built an image for installing 15khz GroovyMame running Windows 7 Embedded so you can write protect the OS partition and not have to worry about powering off your cab and PC at the same time and Windows getting corrupted. It has Attract Mode as the frontend with Windows completely hidden and...
www.arcade-projects.com
Otherwise a mister could be an option.
