what resolution monitor?
What are the temps of the GPUs? perhaps they're overheating? depending on what cards you have, in what case.
Why do you have your fans set to a steady 81% instead of letting them change speed?
Is this a new problem? or has it always been this way?
Is your power supply enough to run these things both at 100% full load (your CPU is probaly near 100% in BF4 as wel)
What is your CPU? it could be a factor here.
Did you disable the ULPS (ultra low power state) in registry?
I had 7950 crossfire and every drive update, id have to go through registry and manually change every string for the ULPS otherwise they'd do goofy things like this.
My ultimate answer, was to sell my 7950s during the bitcoin craze, and buy two 770 4gbs... which was the best decision ever. I have had zero issues in 3 months. Everything works, from the gefoce experience to active vsync.
with my 7950s, it was one issue after another. i had to undervolt, and underclock them to play BF3 for more than 10 minutes without a direct X crash. Nobody on the internet was ever able to diagnose the root cause of that one... i just gave up and accepted it.