Battlefield 4, a sequel to the massively popular Battefield 3 title from back in 2011, and one of the most hotly anticipated games of 2013, might get support for Microsoft's new DirectX 11.1 API, a Windows 8 (and Windows 8.1) exclusive feature that brings further enhancements to the DirectX API.
We use DX11.1, there are some optimizations in it (constant buffer offsets, dynamic buffers as SRVs) that we got in tothe the API that improves CPU performance in our rendering when one runs with DX11.1. This will be in BF4. - Johan Anderson, Technical Director, Frostbite, DICE
It isn't the first time that we are seeing new high-end PC titles to support some new exclusive feature and claim that it does bring improvements, it mostly doesn't bring any significant improvement. Or well, this could just be Microsoft throwing some money into the game and finally getting a title to actually use their new API.