Tiens, je te file la section "Monitor" de mon XF86Config, sachant que j'ai justement un IIayama Vision Master Pro410, que j'utilise en 1280x1024 @85Hz.
Section "Monitor"
Identifier "My Monitor"
# HorizSync is in kHz unless units are specified.
# HorizSync may be a comma separated list of discrete values, or a
# comma separated list of ranges of values.
# NOTE: THE VALUES HERE ARE EXAMPLES ONLY. REFER TO YOUR MONITOR'S
# USER MANUAL FOR THE CORRECT NUMBERS.
HorizSync 27-96
VertRefresh 50-160
EndSection