Basically if you turn 'on' vsync in mantle games now, triple buffering etc gets broken, ie 120fps will drop to 60fps if it even drops 1 fps below 120. Crossfire will drop from 120 to 80. It is occuring in all mantle games ive tested (Bf4, DA:I, sniper elite 3, thief etc). Anyone else confirm? edit: this is with drivers pushed by win10 update & 15.7.1 (also on an upgrade win10 install and fresh iso install.