Man it feels alot more solid and faster connected to the 23" acd, no more expose studdering, I'm sure it has to do with the 512mb vram and it makes a huge difference!! I was installing parallels + connected to the 23" acd + 13+ tabs on safari open and dling from newsgroups and no color wheel ever popped up and not even once did it hiccup and runs super fast. I've done this on the 15" sr mbp 2.4ghz model and it seems to stutter a bit and the wheel popping out once in a while and not as smooth as this 2.5ghz 17" hi res mbp! I do believe the 512mb vram makes a huge difference in driving an external monitor! I'm even considering selling my mac pro and using the 17" with the 23" acd by itself!!