I have troubles with ATI, nVidia and VIA chips. In the past I was able to run s-c-d, pick up proper resolution manually and then set higher resolution (than was in use in the time of s-c-d has been run). Now even I change resolution of my LCD or CRT manually (all in X running), s-c-d does not allow to set higger resolution than actually is in place (even re-run s-c-d). Screen section has no Modes line then (even this is working workaround for most troubles with autodetection of HW capabilities). I have system-config-display-1.1.1-1.fc10.noarch.
Don't use s-c-d anymore. Just run X with whatever resolution you get automagically (you may try just to remove xorg.conf -- it should work pretty well with the auto-discovered values these days) and then change the resolution using gnome-display-properties (or xrandr(1)). Closing as NOTABUG -- configuration issue. Please reopen with the additional information, if you find this explanation not sufficient to resolve your issue.
Working with no xorg.conf is pretty buggy (and I'm trying to report all issues I have for long time with a very little effect). The s-c-d is not installed by default. So the user may expect that if s-c-d will be installed and xorg.conf will be created as workaround, all will work as expected. But this si not possible and s-c-d is broken in F10. See bug #474339 and bug #470217 for Radeon bug with resolution detection. Both may work if proper xorg.conf is created. If xorg.conf is not created, Fedora 10 is useless. This affect more cards, see #475896 for openchrome issue. xrandr is useless when proper resolution (or maximal or virtual for your LCD or CRT) is not detected and the user end up with 800x600 as maximum that xranrd will not be able to pass.
The problem is in the fact, that s-c-d does not write ANY config changes. It just backups the old one and changes the comment line, that config was modified by s-c-d, but there are no modifications according what you choose. The config remains the same - at least for any monitor modification. If the s-c-d is broken why it is included in distro? IMHO: the autodetection is really not that far to leave users without ability to set basic parameters with GUI tool.
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