I'm using a MacBook (2GHz Intel Core 2 Duo) with OSX 10.5.6. When I scroll up and down there is a slight submarining effect with the text. It doesn't actually disappear, rather it "hesitates" or "stutters" as it moves, as though it is about to disappear. It is more pronounced the faster I move the scroll bar. I never have this problem on my old G5 iMac. Is there a Preference setting I can use to eliminate it? I've look at my Display and mouse settings, but don't see anything obvious I can try.