this advanced monitor is 15,4″ widescreen. so after installing ubuntu the monitor only reach 1280×800 not it should be 1680×1050.
first let make the xorg simplying/configuring itself with
#sudo dpkg-reconfigure -phigh xserver-xorg
choose the highest resolution for the monitor.
after that edit the xorg.conf manually
go to Section “Monitor”
add this
HorizSync 60-120
VertRefresh 43-100

that’s all. restart your gnome and i hope the monitor goes fine. actually you can configure the horiz and vert your self until the monitor fit itself to ubuntu. or in the other way.