very bad result with an ultra crossfire of 7970 sometimes I go 50 fps at 45 but I can go down to 15 fps on airport example. I have a i5 2500k overclocked to 4.5 gh

hello, I also have lower performance on the map airport. I have an i5 2500k oc@4.5ghz, sapphire 7970 crossfire, 8gb ddr3. I have 25 to 15 fps on the map airport. my settings: all ultra. depth of field 5600 3000. Please bohemia optimize it for good luck out great games thank you