FPS Limited; Even With Unlimited Set

Whilst testing the new features I realized my FPS was limited to a solid 60, however I had it set to unlimited within the settings.
I am running a pretty 'beefy computer' that should be exceeding 60 FPS. Even with a small render distance it's stuck at 60.
1.6.4 Doesn't have this issue for me.

• I was unable to screenshot the menu so here is the link to an image of my video settings http://puu.sh/4OeLh.png