I'll start with the fact that the 15.6 beta driver
at medium settings
+ - 2-3 frame
but starting with 15.7 driver I had lags.
there is all the information
enable this feature, I get my 30 fps
there are graphical issues
Shadow "blink" etc.
but without this feature
"Default" in the profile settings
loading video card only 50%
on the driver 15.6 I was getting 30 FPS ...