Comment 28 for bug 92599

For future reference: this also occurs on at least one 7x series cards. I encountered this exact same issue with an NVIDIA GeForce 7200GS video card (reported as 7300 SE in xorg.conf under a new Ubuntu 7.10 Gutsy install).

Adding this line to my Device section in the xorg.conf file corrected the issue:

Option "DynamicTwinView" "false"

Otherwise, as NVIDIA has mentioned (as Holger quoted here: https://bugs.launchpad.net/ubuntu/+source/linux-restricted-modules-2.6.20/+bug/104105/comments/9), the video card and display are running at the correct refresh rates, but are reporting different values to Gnome and/or X. Essentially, I had a 50Hz and 51Hz option for 1280x1024 resolution on my Samsung SyncMaster 731B. The 50 selection would really set my refresh rate to 60Hz, while the 51 selection would set it to 75Hz.

Running the following command made this apparent, along with verification from my monitor's OSD:

nvidia-settings -q RefreshRate

So it is fixed for me since I don't need or want "DynamicTwinView". Perhaps others might need this functionality?