this is not anymore since many driver versions freesync works until 20 fps now with frame doubling the same thing nvidia does with g-sync
Be wary of the AMD's LFC (low framerate control) it is very dependant on the monitor used, it only functions when the where max refresh is ≥2.5X min.
http://www.amd.com/Documents/freesync-lfc.pdf
Edit beaten too it.

