Karsten,
I think the problem is that for the fglrx driver defaults to
the EDID provided monitor information to preset the 1600x1200
modeline. I believe the workaround may be to set...
Option "IgnoreEDID" "on"
in the Device section for the fglrx driver so that the preset
VESA modes are never seen by the driver. Then a lower refresh
rate like...
# 1600x1200 @ 58.00 Hz (GTF) hsync: 71.98 kHz; pclk: 155.47 MHz
Modeline "1600x1200_58.00" 155.47 1600 1704 1880 2160 1200 1201 1204 1241 -H
Sync +Vsync
can be used.
Jack
