AMD's Mantle is coming, and when it comes, it should really shake up the performance for Radeon users in Battlefield 4. AMD have said it'll drive 45% more performance in Battlefield 4 when compared to DirectX 11.
AMD said at CES 2014: "It's up to 45% faster than the original version on this same hardware." The big thing we have to take away from this is, if AMD can deliver a 45% performance improvement from Mantle, what is NVIDIA going to do? You can rest assured, as soon as the Mantle update is released, I'll be re-running my SAPPHIRE Radeon R9 290X Tri-X GPUs in CrossFire at 4K, and my triple 1440p setup (4320x2560 and 7680x1440).