Not all games support Crossfire.
What games are you specifically attempting to run, where you're getting worse results?
I have tried watchdogs, the division, need for speed shift 2, battlefield harldine and others
benchmarks like heaven are no issue there is definitely more grunt there, but i was expecting increase in games which im getting hardly anything.
ive just come off watchdogs and single 7970 gives around 3fps more stood in same spot. i might just keep trying to see if i get improvements if not i will trade in the 7950