I upgraded from an 11" 2Gb 128GB to an MBA 11" ultimate yesterday. I have it hooked up to a 24" ACD with wireless keyboard and USB mouse. When I moved windows (safari) around on my stock 11", they moved around the screen without issue, nice and smoothly as if I were using the actual screen of the laptop. With my new ultimate, the windows don't always move smoothly, they appear to lag slightly. It's an obvious difference; it only happens when I have a movie playing at the same time. If there is no movie playing (even open but paused) I have no issues. Is this normal? If not then what could be causing it? Is it possible it's to do with the 10.6.7 update? I never got to use my stock machine on 10.6.7 as my ultimate arrived they same day it was released.