If you have a dual boot system and a monitor / graphics card that works fine under MS Windows but you can't figure out t
he equivalent modeline parameters for Linux, you can use the Windows program PowerStrip.

PowerStrip timing parameters:
1280x768=1280,80,128,208,768,3,7,27,102232,530

Generic timing details for 1280x768:
HFP=80 HSW=128 HBP=208 kHz=60 VFP=3 VSW=7 VBP=27 Hz=75

VESA detailed timing:
PClk=102,23 H.Active=1280 H.Blank=416 H.Offset=64 HSW=128 V.Active=768 V.Blank=37 V.Offset=3 VSW=7

Linux modeline parameters:
"1280x768" 102,232 1280 1360 1488 1696 768 771 778 805 -hsync +vsync