I recently set up a new gaming PC and the tearing on the graphics card (GTX 650 Ti) was horrible. The worst I’ve seen. You probably know that enabling vsync in the Nvidia driver does absolutely nothing — I think they secretly do this on purpose so that people buy the new G-Sync crap.
But there’s no reason for G-Sync. If you want perfectly tearing-free games and videos right now, all you need is the Compton compositor. It’s available in Debian 8. Once you have it, just make sure it’s started at the start of your desktop session:
compton --backend glx --paint-on-overlay --vsync opengl-swc -b
If you think locking your refresh to 60 Hz is somehow bad or if you’re one of those who see the difference between 30, 60 and 120 Hz, that trick won’t be for you. But for everyone else, this is bliss.
Of course you have to disable any other compositor you might already have. I didn’t find out about this myself, I found the reference on the Arch Linux forums. Thanks, you!