If you're in the "Paint Effects" panel, you can turn off redrawing of the paint effects under the "Stroke Refresh" drop down menu - set it to off (its probably on wireframe at the mo). The paint effects still slows Maya down a lot, but you won't have to wait for it to redraw in full every time you do anything. If you want to look at it properly again, click on the "Redraw Paint Effects" button at the top of the Paint Effects panel - it looks like two anti-clockwise red arrows.

You could also hide the paint effects parts. Select them in the "Outliner" (Window --> Outliner), then hide them (Display --> Hide --> Hide Selection). This is probably the best way if you are working on other things in the model and don't need to see the paint effects. To display them again, select them in the Outliner as before, then (Display --> Show --> Show Selection).

Pete.