That depends on the game 3 way sli is not supported well in the majority of games out there, I have seen some games perform worse in three way than 2 way or it can introduce stuttering and other issues. 2 way 780 sli should be enough for for the majority of games at close to max settings 1440p 60fps, however some are going to use more than 3gb of vram so that may cause some performance issues if it does.