One other thing which might help a bit, is to turn the Auxiliary light on. It kills shadows and diminishes most other lights sources in the project, but it does boost FPS a bit.
Otherwise I am so got used to lags, so that when I need to evaluate motions for a particular character and/or apply Live Face for that character, I literally DELETE everything in the scene, save this project as a temp.
And then do all the motions checking, tweaking, record expression track, Save all as Motion+ and apply that track to the main project. Time consuming, but it's best I could do with heavy loaded projects.
Another thing to do is to check if you have too many props in the scene. iClone starts lagging after certain number of props are loaded (literally objects).
Depends on your PC characteristics, but projects with over 200-250 objects (with many materials) would lag on any machine. If you can merge some of them together (both objects and materials) that also might help.