Something strange is going on with my new Crossfire 290 setup. It seems this game can't properly use cards. In same area, I get first 30 FPS, which jump then to 120+, then suddenly I get the drop yet again. That does not happen in any other games, so I believe the FFXIV is to blame. Is there any way to properly configure Crossfire for this game?

Using pair of Sapphire 290 Tri-X with 14.6 drivers.