Ubuntu Gnome Screen Tearing

Hello TekSyndicate forum!

Last month I decided to give Linux a go, using some advice from TekSyndicate and other sources.
I set up my desktop with Ubuntu 14.04 and added Gnome shell after the installation.

I soon noticed frequent screen tearing on games and Youtube videos, but I can't see it on the desktop when moving Windows or typing etc.

I've tried several "fixes" for this including turning of "Undirect Fullscreen Windows" in Compiz, turning on triple buffering in Xorg.conf and changing VBlank and Vsync settings.

It also happens in KDE and Gnome Classic.

Any help on this issue would be greatly appreciated, my specs are as follows:
AMD FX8320
GTX 660 Ti
Ubuntu 14.04.2
Gnome 3 (but happens in other environments too)
Nvidia driver 340 (from PPA mamarley/nvidia)

If you need any more info feel free to ask, many thanks, FizzyFantom.