a long time ago some leagues asked me to screen both monitors as some players had tools on second one , so I did.
the drawback is, it makes more screens and more load.
you have several way to reduce the impact :
– the simplest : swicth off the second screen when you play
– the techies one : most mobos have an internal GPU , you can activate it and plug the second monitor on , it will be handled bythe internal gpu and switching from game to desktop will be faster, game gpu’s will be dedicated to game and wont have to deal windows desktop, Moss’s screenshots of 2nd monitor wont load the game gpu and thus have less impact on game.