Comment 20 for bug 92599

It looks very similar, indeed. Although I don't use TwinView, the refresh rate seems to be reported correctly by monitor's OSD and nvidia-settings, but not by Gnome's screen resolution setup dialog and xrandr command.

Here's the output of "nvidia-settings -q RefreshRate"

   Attribute 'RefreshRate' (Xel-Naga:0.0; display device: DFP-0): 75,02 Hz.