Mmkay, I posted a couple days ago about how my Radeon 9800 went utterly berserk after waking from sleep one day--screwy horizontal lines all over the screen. Showed up as toast in hardware test, I called AppleCare, and they overnighted me a replacement. Got here today (thank goodness it made it by Friday) and I installed it, and I'm ALMOST back in business... except now, once in a while, I'll get these little regularly spaced quarter-inch long diagonal lines of black pixels when a new window is created or refreshed (for example, loading a new web page). A small screenshot is attached for reference. They're definitely part of the image map of that object, as they go "under" the mouse and scroll with the window, and redrawing it (for example, scrolling out of sight then back) removes them entirely. Anybody else seen this before? The short hardware test showed no problems, and I'm going to try blowing out the slot and reseating the card (would have already if that screw wasn't such a massive pain--I have lost it in the guts about a dozen times just swapping cards twice), but if that doesnt' do it I can only assume it means my logic board (or AGP slot, I guess) is going since the chances Apple shipped me a bum card are slim. Could be a software issue, I suppose, but the timing would be bizarre, and a reinstall to test isn't at the top of my "fun to try" list.