Not exactly. SmoothMAME modifies game's drivers which have a frequency different from 60hz. If a game runs at, for instance, 57 or 55 hz, and your screen refresh is set to 60hz, those games will move jerky, due to the missmatch (when synced: using vsync or tripple buffer, for good scrolls and not tearing). You could adjust your screen refresh to match those games, but that's a mess, because there are dozens of different refresh rates and many games affected. It's much easier to tweak refresh rates of the emulated games rather than the refresh rate of your own card. Games will run a little faster (depending on the missmatch), but you will not have to worry about jerky scrolls or setting refresh rates anymore. This is even more interesting if you use native screen modes (ArcadeVGA), because you will be using many screen modes for different games, which have been set to 60hz.