xorg.conf after installing xorg-driver-fglrx It can be easily seen that the monitor has not been properly detected, and maximum frequency was set at 60hz.
I restored the original file, modifing it as follows: ------------------------------ Section "Device" Identifier "ATI Technologies Inc RV370 [Sapphire X550 Silent]" Driver "ati" BusID "PCI:1:0:0" EndSection ------------------------------ changed to: ------------------------------ Section "Device" Identifier "ATI Technologies Inc RV370 [Sapphire X550 Silent]" Driver "fglrx" BusID "PCI:1:0:0" EndSection ------------------------------ Added the following block: ------------------------------ Section "Extensions" Option "Composite" "0" EndSection ------------------------------ Restarted X server and all went fine. ** Attachment added: "xorg.conf" http://librarian.launchpad.net/6996131/xorg.conf%7E -- xorg / fglrx doesn't recognise monitor modes correctly https://launchpad.net/bugs/22122 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs