Here is how I solved vsync issues for video on my ASUS K50IN notebook with the NVIDIA Ge Force G102M. Open nvidia-settings and change the Frecuency from Auto to 60. This solved my problems with the video tearing and the general desktop flickering. I was experiencing the very same video tear problems.
I am aware that your mileage may vary since the cards are different, but you can try it out... In my case I observed that tear down happens in fullscreen mode only.
The trick for me was to use barebones MPlayer (but not MPlayer2! The problem seems to be at scaling the video to fullscreen.
Setting the aspect ratio in smplayer to the displays aspect ratio fixed the problem for me. I was playing a 1280x714 sized video in fullscreen there was tear in the video.
As I forced the aspect ratio of the video to 16:9 the playback was smooth.
I have to note that the root cause of the problem stays there and is annoying.
Open nvidia-settings and go to the powermizer section.
Choose "Maximum Performance" in the drop-down, and you should see your powermizer level jump to the fastest speed. In the past, I've found that vsync doesn't work when the nvidia card is on the slowest powermizer setting. This is effectively impossible unless both monitors are the exact same type.