in hyprland you can mirror monitors of different framerates, but the mirrored monitor doesn't re-render the display. so unless the framerates are equal (or the mirrored monitor's framerate is divisible by the mirror), frames will be lost. but what does that look like at higher framerates?
afaik x11 can't handle different refresh rates across monitors and simply ends up displaying a subset of the highest rate across the other monitors, so this could be used to check for stuttering as a result of indivisable framerates here.
above ~90hz i can't see frames being skipped. i have a 144hz monitor and a 120hz tv, and was wondering if i should set them both to 120hz when i'm optimizing for viewing on the tv.
i record the glxgears rotating gears program with my iphone 11 which is able to record in slow-mo 240fps.
in the slowed footage it is obvious whether frames are being skipped or not.
i am able to confirm that 120hz mirroring 120hz is smooth, rendering each frame.
and that 120hz mirroring 144hz stutters, skipping frames in such a way as to make the spinning of the gears appear jerky.