RGB on SFZ3 Saturn?

I was curious to know what the difference was between 'normal' and 'rgb' modes in my Street Fighter Zero 3 for the Saturn? I have no idea what it means or if I can even take advantage of it.

Anyone know?

That option is also on Vampire Savior from what I recall, although it is listed as S-Video/RGB. I have no idea what it does to the game's display output though, perhaps it enhances/reduces some color saturation to compensate for using composite or rgb.