I have never had this rig on a 60Hz display and never measured the FPS either, but if V-SYNC will help gain FPS and will not cause me to lose FPS i guess there is really no good reason to shut it off, Thanks for the help guys.
You misunderstood what I said.
V-sync can cause you to lose FPS. What I was saying is that if you had a monitor with a 60hz refresh, and while using this monitor, you had over 60 FPS without v-sync, and were at 60 FPS with v-sync on. In this condition, moving to a 120hz refresh rate would increase your FPS above 60, while v-sync remained on.