After reading tons and tons of manuals and forums about the problem I need to ask myself, because I can't figure out what's wrong.
In my new PC there's a GTX 660 connected to LG Flatron L1730S using D-SUB / DVI connetor. This monitor is able to work at 1280x1024 with 75 Hz refresh rate and I'm not able to set it anyhow.
I can create a new mode in xrandr but I can't connect it with DVI-I-0 output to which my monitor is connected.
After
xrandr --addmode DVI-I-0 1280x1024_75.00
I get this:
X Error of failed request: BadMatch (invalid parameter attributes)
Major opcode of failed request: 140 (RANDR)
Minor opcode of failed request: 18 (RRAddOutputMode)
Serial number of failed request: 39
Current serial number in output stream: 40
It's been two days now, and at 60 Hz I get my screen is flickering.
Please, help me get it right.
PS. I use nV proprietary 331.113