I don’t know about GNOME but in KDE I needed to do it like that to have good experience in web browser, video players, and games Fix screen tearing on KDE with Nvidia - Album on Imgur but maybe you could check with google if GNOME has maybe other tweaks. Also the WIKI is usually a good place to find some tweaks.
Did you try a very long web page where you scroll down more and more quickly to see if at some point you got horrible tearing? Wikipedia or big announcement threads here is good for testing.