Apple Cinema Display (30-inch DVI) might show 1280 x 800 as maximum resolution

When you connect an Apple Cinema Display (30-inch DVI) to your computer, you may find that the highest available resolution is 1280 x 800 even though the optimum resolution for the display is 2560 x 1600. This can happen if the display has a single-link DVI connection instead of a dual-link DVI connection.