I have video tearing with compositing enabled in KWin.
I have 2 monitors in twinview, VBlank is set to sync with one of them. I have some tearing on that monitor anyway, and it's much worse on the other one.
The horizontal tearing occurs everywhere on the desktop, I can see it when dragging windows and such.
I'm on 12.04 with the proprietary 302.17 drivers. VSync is enabled everywhere (in KWin and nvidia-settings). I have nvidia-settings --load-config-only in startup.
The only way I can get rid of the tearing is to disable compositing, and I don't want to do that. Compiz can run with no tearing, so should KWin.
I have tried everything, I don't know what to do anymore. I've been googling for weeks. I am at my wit's end.