So I have 3 screens on my Mac Pro and pretty much since I installed my 3870 the 2 20" screens redraw weird. I really only notice it in Preview and System Preferences (Desktop & Screen Saver and Displays). It's most annoying in Preview since I'm not in System Preferences all that much but... yeah. Anyway some screenies below along with my lane configuration in case that matters. The 30" is ran on the 3870 with the 2 20"'s on the x1900.