I have a late 2008 MacBook (5,1). I have a mini displayport to single link DVI connector which allows me to hook it up to my 47" LCD screen using a HDMI adapter in my house and I get 1920x1080p on the external screen. However, I have an Apple Cinema 30 in the office and cannot get better than 1280x800 on it, lid open or closed, booted with lid closed, doesn't matter. Any ideas? Do you need a dual link cable for the 30? I don't see why as the 47" at home displays 1080p just fine with this cable.