ThatVietGuy :
Vsync will cap you at your monitor's refresh rate.
You should upgrade from a GTX 1070 when you feel like it can no longer do the job you want. This is entirely dependent on your personal graphical/gaming preferences.
Also when i turn v-sync on will the fps count the monitor fps or the fps that the gpu is exerting? For example, if I turn vysnc on for a monitor that has 75hz, will the fps counter never go above 75?