Not 100% sure, but I think before Capcom made their four meg cart they thought it would be a three meg model [Cyberbots has the option also, while Pocket Fighter has a 1/4meg option IIRC]. Anything to best SNK's 1meg I guess. Anyway, it works fine with the 1/4meg carts. Honestly, I can't tell the difference between with and without the extra RAM on any three of the games.