I've been running dual monitors as similar to chizow. i use it to monitor vent and guild info. I was using an HIS x800xl up until about a month ago. I had no issues what so ever with running dual monitors. I could drag crap back and forth and tab through windows, etc and didn't see a single problem - hell I was running two copies of WoW and still didn't see a problem. I upgraded to an HD3870. Now, if i drag a window (i.e. browser) from the second monitor to my primary, things get all jumping and basically, my system freaks out. So, my answer would be - it depends. Perhaps I have an isolated issue.