Tommy there are lots of games that aren't playable in Mame. Try Carnevil, it's the same way.
Mame is an emulator, and that means it has to pretend to be a complete control system for another system. Carnevil and Crusin USA are working off systems designed for graphic speeds. Your PC can't keep up, because it can't process the data that fast.
From what HowardC told me, and he's da man on these issues, you need raw computing speed to run mame. The graphic cards are nice, and the ram is nice, but 1.7GHZ won't cut it.
When they get to 5 GHZ or better, it may run. But for now, it's just doing the best it can.