so recently i have been playing bf4 with amd's MANTLE thing. the max settings i could play at were low at 1902x1080, at prob 45fps. i wanted to try playing on directx just to try it, so i put it on directx. suddenly, i could play at low on 60 fps. so i tried going up to medium, and that was 60fps. i tried going to high, that was 60fps. i tried turning all the settings to ultra, and with a bit of overclocking, i maintained 60 fps on ultra. why doesnt mantle work at all. when i try the ultra settings with mantle on, i get probably 10 fps. i dont get it. i even have all the latest graphics drivers installed. btw my card is a radeon hd 7790 1gb, with a fx-6300 @ 4100MHz