Sorry not been on here in a long time, Crossfire didn't actually work with the dirt3 profile in the end, the usual bugs reared their ugly heads not long after i posted.
I no longer have 2x7970's, i got rid of them last November and am now running a R9 Fury....the game has run much better since, well over 60-120fps....The only problem i have now is the frame times, they are all over the place and the game is very stuttery....