If you are using Multi-Monitor for gaming, you won't be able to watch Youtube Videos on Fullscreen at different displays, unless you open the ingame Browser just like Steam or Origin has, otherwise you'll can do just as I do.. I have a TV and a Monitor but my Main Screen is set to Monitor and is extended with my TV, any time I want to play a game I can select in which display I want the game to play on by either tweaking NVIDIA or Windows display settings by setting the main display screen. Basically you can run the game on one of your monitors and drag Chrome or any browser you are currently using to the other and watch youtube videos while playing, but bear in mind that.. you'll may experience a lil stutter in the process since you'll be rendering the game and the youtube video.