Yes, does not apply to the present case.
This is not drop frames in layers window. This is how I see some times braking of video. Not with constant periodicity.
I also thought about it and conducted an experiment with 60 and 75 refresh rate of full screen and 25-30 frames movie. It does not affect.
50 herz no good frec for some led screen equipment.
I have 10.6.8 OS.
Ok. А good experience!
Thank you!
P.S. Need more layers, need additional widget for light console!