It will increase speed but you will also need to shoot a heavier arrow out of it, my bow at 80# with a 400gr. arrow shoots around where it would with a 350gr. arrow at 70#. The other factor is that you will likely not be able to shoot as much daily because the heavier bow will wear you out quicker. I have friends that shoot 70# bows all day long and can barely pull my bow at 82.2#. You will also get shakier on your shots as you increase your draw weight because of muscle fatigue. If you want to shoot a 400-500 gr. arrow with a lot of KE and speed then 80# is not a bad call if you can pull it, or you can lok into bows like the 82nd.