If you are on pc and you either ALT+TAB or use the Winsows key to use your browser etc, you need to be careful, if you keep hearing the game in the background while on your desktop then GO BACK to your game and repeat the process until you cant hear the game while browsing or in the desktop.
WHY?, well because if not for some reason the game starts overheating your GPU, making it work like crazy, my card starts even doing a weird sound when this happens and then i check my temperatures and they start going up consistently when in this state and it calms down when i make sure the game dosent sound in the desktop, so be careful about this.