Well, AW currently has issues as a product itself. The latest patch that came with the DLC partly fixed most of them, but there are still issues in launching the game for many players to begin with, so I'd say it's the game's fault. CoD games never favored a GPU manufacturer over another tho, so I doubt that's the issue either.
Also, I don't own BF4, but since it's powered by an in-house engine and supports Mantle, I doubt it favors Nvidia...
The thing is, at least from what I know, that an overclocked 8320 shouldn't have too many issues in handling a Crossfire/SLI solution (while still usually being somewhat underperforming compared to an Intel), especially if overclocked up to 4.5Ghz. I could understand if it was down at its 3.5Ghz stock, but up there it's very unlikely.
1) Do you have any other game you can try with a similar load to those two?
2) Have you tried running the games in single GPU mode? Since you have a dual-GPU, you shouldn't have a global settings (AFAIK). Add a 3D application profile for those games in the CCC, and you should be able to disable CrossFire usage there.