If you are trying to change settings in NVIDIA Control Panel but can't save the settings, follow this post and apply these fixes to resolve the issue.

NVIDIA Control Panel Custom Resolution is greyed out or not showing up 1] Update your NVIDIA display driver If you experience the NVIDIA custom resolution not supported by your display issue, the ...

In the NVIDIA control panel, as well as in your game settings and Windows display adapter settings, make sure your screen resolution and the monitor refresh rate are set to the proper settings.

NVIDIA is testing out a new unified app that lets users adjust GPU settings, install software and fine-tune gameplay, all from the same place. Currently, you have to access the dated Control Panel ...

It still has a ways to go, but the gap between NVIDIA App and Control Panel closes a bit more as updates roll out for the ...

NVIDIA App 11.0.3 just some great new features, the ability to fine-tune DLSS Super Resolution and more legacy Control Panel display options.