Hey guys i have a 15" MBP i7 with 4gb ram. Im having some issues whenever i connect to my 27" cinema display. If i leave the lid of the computer open(both screens on) there are no issues, but if i use it with the lid closed, which is the way that i need it to work, it becomes almost unusably slow for certain applications like autocad and iphoto in full screen. I bought the display to use with autocad with my laptop closed to preserve desk space. Any ideas?