I have this same problem that others did above and haven't yet found a solution. Just to re-cap the situation: When I switch from the four-pane view (or any more-than-one-pane view) to any single-pane view, tracking, dollying & zooming all become really laggy. Also: When I initially open a scene, the default single-pane perspective view has no lag, only when I make it large. Did anyone come up with a more graceful solution that "restart Maya when it does that" (it happens everytime I switch views)? Thanks