Smart Mouse doesn't seem to matter.
I've found Smart Mouse doesn't have any effect on screen stutter/tracking, on or off. In fact in games like L4D2 with smart mouse off you lose your pointer. You also, generally, have poorer mouse performance.
This seems to be a core issue with Parallel's mouse emulation. Playing a twitch based first-person shooter reveals the bug more than slow-moving Skyrim as well. If you dart left and right with your mouse you will see the screen "skip back" slightly in the opposite direction you were moving. This often leads you to pointing in a direction not intended by your movements. Which in turn can make you dizzy in real-life! lol.
I hope the devs can look at this. Because sans that, playing games in Parallels is nearly always better than anything I've seen from the "real" ports on Steam or in the App Store.
For the record my Skyrim settings are...
1440x900
HIGH (no AA, doesn't seem to work in any game as is. Para bug?)
4GB of my 8GB for P7. 1GB to video and all 8-cores from my (2010) i7 iMac.
This gets me smooth fps once things are loaded with only the occasional stutter as the swap file is hit back in OSX to feed Para's ram needs. I know an SSD and another 8GB (16gb max) would make P7 game playing nearly a seamless affair. Just waiting on that tax return.
"He Who Is Too Lazy To Run Bootcamp And Enjoys Watching Windows Dance For Him Inside Osx."