xorg.conf snippet for a Samsung SyncMaster 2253LW monitor.
Full specs here : http://downloadcenter.samsung.com/content/UM/200801/20080105125513265_BN59-00671A-Eng.pdf
Section "Monitor" Identifier "Monitor0" VendorName "Samsung" ModelName "SyncMaster 2253LW" Option "DPMS" HorizSync 30-81 VertRefresh 56-75 # 1680x1050 @ 60.00 Hz (GTF) hsync: 65.22 kHz; pclk: 147.14 MHz Modeline "1680x1050_60.00" 147.14 1680 1784 1968 2256 1050 1051 1054 1087 -HSync +Vsync # 1280x1024 @ 60.00 Hz (GTF) hsync: 63.60 kHz; pclk: 108.88 MHz Modeline "1280x1024_60.00" 108.88 1280 1360 1496 1712 1024 1025 1028 1060 -HSync +Vsync EndSection Section "Screen" Identifier "Screen0" Device "Card0" Monitor "Monitor0" DefaultDepth 24 Subsection "Display" ViewPort 0 0 Depth 24 Modes "1680x1050_60.00" "1280x1024_60.00" "1024x768" EndSubSection EndSection