my sapphire 7970 is always stuck at 475 / 710 even when games are loaded. when i try to overclock with sapphire trixx, and i check it with gpu-z, it says my clock speeds are 1100/1600. but when i load a game (tomb raider) i get huge lag unless i openup CCC and enable the overclock drive. if CCC overdrive is not enabled then my clock speeds are still 475 / 710 . any solution to this?