How do I set up different MAME cores per game when using Retroarch module?

[chipsnowdrop]

I use MAME core in retroarch as my main core but some of my games don't work with it and will require Final Burn Alpha core for them to work. How do I set some games to start with FBA core instead?

[dark13]

If you want to use vanilla mame on some games and RA on others you need to create a new emulator and use alternate emulator feature. Just as example: virtua fighter kids in latest mame release runs at 30%, with older mame release it runs 100%. For ST-V you can also consider Kronos core in RA (it has some issues with v-sync on some games).