Hello.
To make SDDM work correctly on my G-Sync monitor, I had to add this manually in /etc/nvidia/nvidia-application-profiles-rc:
{ "pattern" : { "feature" : "procname", "matches" : "sddm-greeter" }, "profile" : "No GSYNC" },
Otherwise, the mouse cursor and keyboard input is extremely choppy. SDDM is probably one of the most widely used display managers out there.
Same goes for using the XFCE desktop environment. I had to add this:
{ "pattern" : { "feature" : "procname", "matches" : "xfwm4" }, "profile" : "No GSYNC" },
Otherwise the desktop is virtually unusable (extreme stutter and very unresponsive UI.)
I think these entries should be added by default by NVidia.