Samsung PN51E6500EFXZA - Manual (Page 238)

console and connect another external
device, set Game Mode to Off .
– If you display the TV menu in
Game
Mode , the screen shakes slightly.
N Game Mode is not available when
the input source is set to TV.
N Set Game Mode to On only after
connecting a game console. If you
turn Game Mode on before you have
attached the game console, you
may notice slightly reduced picture