Originally Posted by WookieeCookie
I generally play LoL in Windowed Borderless Mode. That way when you alt-tab out it doesn't take nearly as long, and when you're playing the game it still looks like it's Full Screen.
Your performance may vary though depending on your computer's hardware.
Was so happy when you guys added this. I hated it when a Skype notification or something would minimize my game, and I had to stare at a black screen for 10 seconds before I could get back in, knowing full well that I had probably already died.