When I play titanfall with enable crossfire X, the graphics performance is aweful. Very very low frame rate, rendering speed and stuff like that. Funny thing, when I disable crossfire, overall performance are fine. So dual GPU can't beat single GPU in my situation.
My PC spec.
MB: ASRock Z170 extreme 7+
RAM: Teamgrupp PC4-19200 8GB x4
VGA: Radeon PRO DUO