@churchill7 in mame2003-plus and mame2003 this core option will be hidden unless you're playing a game that uses the feature. I recommend running pacman then going into the core options.

https://github.com/libretro/mame2003-libretro/blob/7ea22d44c0d899cf7670d458cd6dac0942839d2d/src/mame2003/mame2003.c#L187

The default is probably decent though like you observed in Tron.