Thanx guys for your answers.I just called nvidia-settings as root,choose 1680x1050, wrote the changes to xorg.conf without merging it, and i got 1680x1050.First i had to choose a 4/3 resolution to pcc otherwise the nvidia settings had only lower resolutions to choose from.
Thanx for your time and sorry for my bad english.I am sure i ll have much more to ask.So be well for now.