I'm running - on a dual 2ghz G5 - the apple 30" cinema display powered by the ATi Radeon X800XT mac edition graphics card. Both display and card are a little over a month old.

Everything has been fine until today - now vertical bands of yellow blocks ( almost a tyre tread pattern) appear across the screen. Neither changing desktop background or screen resolution gets rid of them. They appear all over the screen.

Is the card? Is the display? Anyone seen this and has a solution?