Okay, thank you for your answer. I play mainly shooting games / FPS and often several characters simultaneously, which means that you have to have a number of images per second enough to be effective enough conscience and not stupidly miss its target. That's why I disable the vertical sync, because even if what I see actually remains 60 IPS, I notice that when the game is unrestrained at 120 - 130 IPS, I still get a little better ... Finally, it's no doubt a bit silly but it's just a personal feeling. With that, thank you all for your explanations and good evening to everyone.