Many modern screens (with 16:9) don't properly get (DDC? or successor?)- autodetected yet. Try a few settings with a hand-crafted /etc/X11/xorg.conf. I had the same problems when I bought my gf a Fujutsu tft panel last month. I must check later, but it was something what exactly the setting is which made it operate smoothly in circa 1600x900 (on a Radeon 7000 inside Sempron64 1.8GHz Eleitegroup something PC).
Don't give up early. /etc/X11/xorg.conf is what you should concentrate on. One other thing that you might try: Start the Xserver in some conventional res., such as 1024x768. Then ease up trying different resolutions by making use of the Resize and Rotate extension (RandR) - under Gnome: Right-click the desktop and choose [Screen Resolution] and try what it offers you. It may be, that you will being offered resolutions, that may not be the highest ones, but which are at least in 16:9. Which doesn't provide more space an the desktop, but which looks significantly better, than a modern 16:9 panel running in a conventional 12:9 res. %martin
