I'm using Ubuntu 13.04 64 bit for the past short time. After a screen upgrade, I can't use/set the right resolution.
My old display setting was three 17" of 1280x1024 behind a Matrox TripleHead2GO connected to a Nvidia GTX480. All was working fine with a virtual resolution of 3840x1024.
(TripleHead2GO emulate a single screen of the total resolution for the OS.)
Now, I've upgraded to three 24" of 1920x1080 for a virtual resolution of 5760x1080. But I don't see this resolution on the Ubuntu Display Settings nor in the xrandr list.
How should I use this higher resolution?