Upgraded two PCs from Core 5 to Core 6. Also upgraded monitor from Samsung 17" to Samsung 20.1" wide. Fedora did not detect new monitor. Still shows old one as being used.

Also did new install on two other PCs. Again did not detect new monitor and set display to default 800X600. Manually changed to new display resolution of 1680X1050. Now get box floating around screen that says something like invalid resolution?

There are at least three places in Core 6 GNOME to set screen/display resolution. They don't even agree. Changing any of them sometimes changes xorg.conf, sometimes doesn't.

Can someone explain what the difference in the three settings is? Also why do I get the box when I manually set to 1680X1050? And is there any way to repair?
Terry

If your monitor and video card can handle it you could try using "gtf 1680 1050 60 -x" to generate a modeline to try.
Change the name of the modeline from "1680x1050_56.00" to "1680x1050_56". The 56 is the refresh rate. You might want to use a different number.

Thanks. Have to go to work so no time now. My MOBOs are all nVidia 6150s with AMD 64 CPUs. The other three still usable installations are actually displaying 1680X1050_60 just fine - I think. That is with Administration-Display-Monitor set to Default LCD 1280X800. From GNOME under Display-Monitor the Default LCD settings do not give you any option for specifying Analog or Digital, or the refresh rate. Could have something to do with this. Wish I could find something that defines exactly what the three separate GNOME Display settings actually do? Seems like with Display-Monitor set to Default LCD 1280X800 that Display-Screen Resolution is somehow autodetecting the 1680X1050 screen resolution. But sure is confusing!

Still working on this issue. Monitor is Samsung 204-BW. Resolution is supposed to be 1680X1050@56 or 60 HZ. That is a .625 or 16:10 ratio. When I set to ANY of the .625 or 16:10 ratios in Core 6 the screen size is to tall and you can't see the bottom. If I set it to a .6 ratio, 1280X768 for example, it displays correctly. The .625 or 16:10 settings work correctly in XP. Why must they be .6 in Core 6? Think the earlier problem was related to the refresh rate. Went into xorg.conf and changed that to 56-60 from 56-75 and that seems to have solved the earlier unable to display at all issue.

Finally got one of my PCs to talk nice to this Samsung 204-BW LCD. Went into BIOS and turned off everything that is not being used. Stuff like parallel ports, serial ports, USB, Firewire, etc. This particular computer is an AMD-64 FX-55 on a Foxconn nVidia 6150 chipset MOBO. Then for the umteenth time installed Core 6 32 bit version and low and behold the thing finally recognized and auto configured the monitor as Samsung Syncmaster at 1680X1050 60 Hz like it is supposed to. What turning off the other stuff is BIOS has to do with anything is beyond me but that apparently is what solved this MOST frustrating problem, at least on one of my computers.