http://anandtech.com/show/9811/amd-crimson-driver-overview/3
"AMD does note that LFC is only enabled with monitors that have a maximum refresh rate greater than or equal to 2.5 times the minimum refresh rate (e.g. 30Hz to 75Hz), as AMD needs a wide enough variable refresh range to run at a multiple of framerates right on the edge of the minimum (e.g. 45fps). This means LFC cant be used with Freesync monitors that have a narrow refresh rate, such as the 48Hz to 75Hz models. Ultimately owners of those monitors dont lose anything, but they also wont gain anything with LFC."Will LFC work on the acer 34" predator monitor?
Which other monitors too?