A recap of the problems for my configuration: Centos 5.2, x86_64, PNY 9600 GT 512 Mb video, Rosewill R913J 19" LCD monitor, Gigabyte GA-P35-DS3L mobo, Intel Core 2 Duo, 8 Gb RAM.
Using the latest Nvidia x86_64 driver package (177.82) I could not get the 1280x1060 resolution (I could get nothing but 640x480).
Additionally, while attempting various fixes, the monitor base color turned blue.
Cure:
0. I set run level 3 in /etc/inittab and then executed 'telinit 3' to work from a text display.
1. I set the Rosewill in VGA (analog) mode--that is the only mode that will work with the Nvidia driver (discovered by trial and error).
2. I deleted the existing xorg.conf file (at /etc/X11).
3. I used nvidia-xconfig to write a new xorg.conf file.
4. I initially tested with startx, but that didn't work with my set up. I found that using "gdm" let me see a successful X server.
5. After a successful X start at the desired resolution, I then set run level 5 and executed 'telinit 5'.
Weird monitor base color:
6. To reset the monitor base color back to normal I had to clear the BIOS CMOS memory and reload the BIOS defaults.
Note that the Nvidia list of Linux-capable video cards at http://www.nvidia.com/object/IO_18897.html (thanks to John Stanley) is the one to consult to ensure a card is usable under Linux.
I have found no card manufacturers with any significant degree of tech support for Linux, so I cannot recommend one over the other (over the years I have tried cards from MSI, XFX, EVGA, PNY, and others, but it was always hit or miss--I usually looked at the READMEs with the Nvidia driver packages but that has proved to be unreliable for me--once more, thanks to John Stanley for pointing out the other list that I have always overlooked).
I hope this helps others with weird video problems.
-Tom
Tom Browder Niceville, Florida USA