Sounds like you need to set your monitor to 1280X1124 in X. You didn't mention your distro - but the place to look may be /etc/X11/xorg.conf. If you look in that file you should see a section for monitors. Mine looks like:
Code:
Section "Monitor"
Identifier "monitor1"
VendorName "ViewSonic"
ModelName "ViewSonic E790"
HorizSync 30-95
VertRefresh 50-200
# Monitor preferred modeline (75.0 Hz vsync, 80.0 kHz hsync, ratio 5/4)
ModeLine "1280x1024" 135 1280 1296 1440 1688 1024 1025 1028 1066 +hsync +vsync
# TV fullscreen mode or DVD fullscreen output.
# 768x576 @ 79 Hz, 50 kHz hsync
ModeLine "768x576" 50.00 768 832 846 1000 576 590 595 630
# 768x576 @ 100 Hz, 61.6 kHz hsync
ModeLine "768x576" 63.07 768 800 960 1024 576 578 590 616
EndSection
and one like:
Code:
Section "Device"
Identifier "ATI X300"
Driver "radeon"
#VideoRam 131072
# Insert Clocks lines here if appropriate
EndSection
finally there is also a section like:
Code:
Section "Screen"
Identifier "Screen 1"
Device "ATI X300"
Monitor "monitor1"
DefaultColorDepth 24
Subsection "Display"
Depth 8
Modes "1280x1024" "1024x768" "800x600"
EndSubsection
Subsection "Display"
Depth 15
Modes "1280x1024" "1024x768" "800x600"
EndSubsection
Subsection "Display"
Depth 16
Modes "1280x1024" "1024x768" "800x600"
EndSubsection
Subsection "Display"
Depth 24
Modes "1280x1024" "1024x768" "800x600"
EndSubsection
EndSection
which ties the monitor and the vid card together.
HTH