Originally Posted by AaronP
There is no way to synchronize to two displays at the same time because they could be running at different rates or out of phase. It's surprising that you didn't see tearing with older drivers.
zsnes has some modes that use OpenGL and some that don't. Are you sure you're using one of the OpenGL modes?
No problem. Allright, thanks. zsnes is using 640x480 ODS mode, I think it means it uses OpenGL, and scales to full screen.
Also, I think because I was running the wrong version of nvidia-settings, I couldn't switch what display to vsync on. If I switched it and closed nvidia-settings, it'd go back to having the other selected. The current version doesnt do that. That was my main issue, thanks!!
But still, odd. Why are OpenGL games able to sync on both screens, or is that my imagination? Is it possible that the syncing code for that can delay refreshing on each head separately, or something? mplayer -vo gl doesn't tear on either screen, so I guess I'll just use that for playing video. XV tears quite noticibly on one screen or the other depending on what display it's synced to.
If you want to reproduce it, it's as simple as taking a video, and two screens in twinview clone mode
mplayer -vo xv whatever.avi
One will tear
mplayer -vo gl whatever.avi
Neither will tear