I'm not sure, I have a 7990. The most stable I managed to get it is 24-30 odd fps. That is at 1080p with a combination of low and medium settings. That is running off of one gpu. I try both gpu's with default settings in CCC and I get a slightly higher frame rate, but it becomes a stuttering mess. Things are improved, both performance and stutter, when switching to AFR mode for Crossfire (even when I go to my native 1440p resolution), but then the entire map vigorously flickers enemies etc become almost invisible etc.
When using 1 gpu, I can turn some of the settings I have on low to medium and the frame rate doesn't change, but it does have more micro stutter. It's took me many hours of tweaking various settings to get where I am. So I have it just about playable frame rate, by lowering my resolution, putting settings on a combination of medium and low (I set post process to medium). It's not acceptable, especially as I know with crossfire working properly, I can get 40-60 fps in my native resolution, with more settings put up.
I have lower tier single gpu cards stomping me in performance, whether I use 1 gpu, or 2. I can't explain reasons why that is the case. I know the 7990 I have is not among the best of 7990's (in honesty it's been more trouble than it's worth), but it should not perform as bad as it does, even with just 1 gpu.
I actually need drivers, if not at the very least to perform a stable 30fps in my native 2560x1440 resolution. Whether that can be achieved with 1 gpu or 2. Knowing that I am currently watering down the visuals for the game to barely run is actually making me enjoy it less. Especially when I know my hardware is more than powerful enough to run it a lot higher than I currently am.
