> I did a little more experimenting and learned my G550 doesn't need
> nomodeset for the MGA X driver to work, but it only produces 1920x1080
> on my 2560x1440 screen, and xrandr still can't identify output names.
You can trying playing with "modelines" where you reduce the screen
refresh rate to 30Hz to keep the "dot frequency" below the card's limit.
Contrary to CRT, current displays tend not to need as high a refresh
rate to avoid flicker. Of course a lower refresh rate may encounter
other problems (e.g. your display may simply refuse to display it).
Stefan
