I've got the Dell 30 inch and 2 Samsung 19'' monitors running on a X1800XT and a X300 video card. Here is what works and what doesn't, PLEASE HELP! (1) Both video cards run Aero on two monitors by themself, with the other video card unplugged, so both cards clearly qualify for aero. (2) The Dell and a Samsung run aero off the 1800 video card with the X300 monitor disabled. (3) The Dell and both Samsungs (one Samsung on the X300) run aero IF the Dell is set at any resolution below 2560x1600. (4) PROBLEM: The only time Aero does not work is when all three monitors are enabled AND the Dell is set to 2560x1600 resolution. Again, any resolution under 2560x1600 on the Dell will enable Aero, and disabling the X300 Samsung monitor will enable Aero. (5) I've substituted the X300 video card for another 1800 series video card (so running two 1800 video cards) and the exact same outcomes as above occur, so its clearly something quirkly with aero. (6) I've got the latest ATI drivers, uninstaled them trying to add the video cards seperately and together, still doesn't fix it. I've updated my computer rating in Vista, which is 5.7. However, every time I have all three monitors enabled and the Dell at 2560x1600, aero gets shut off. Other info: I've got 4 gigs of Corsair XMS PC 6400 Ram and the E6600 C2D running at 3.2ghz. I've probably spent 5 hours trying to fix this aero issue. Hopefully someone has some ideas. Thanks!