The release of a Direct X 12 API may still be uncertain, but that has not stopped Microsoft from building upon the existing DX 11 API. Specifically, Microsoft has announced an update in the form of DirectX 11.2, which makes some back-end tweaks and adds some new gaming-related features.
First shown off at BUILD last month, Antoine Leblond demonstrated Direct X 11.2, and one of the API's major features: tiled resources. He did not go into specifics, and Microsoft has not yet released documentation on DX 11.2, but during the presentation Leblond described tiled resources as a mechanism for supporting very high resolution texutres by allowing the game engine to use both dedicated graphics memory and system memory to store and read texture data. The demo reportedly featured 9GBs of texture data, which was shared between GDDR5 and DDR3 memory.
I am not certain on exactly how this "tiled resource" technology differs from what current games and hardware is already capable of, where the graphics card can use some amount of system RAM for its own purposes when it has data that cannot be stored in the limited GDDR5 space. Perhaps Microsoft has found a way to make the swapping process more efficient, or it could be a completely new way of enabling shared memory that would support HUMA/HSA-like strategies behind the DX abstraction layer to make it easier for game developers. This is all speculation, however.
The other major takeaway from the announcement is that the new DirectX 11.2 API will be exclusive to Windows 8.1 PCs and the company's Xbox One gaming console. It is suprising that Windows 8 is not included, but seeing as Windows 8.1 will be a free update it is not that big of a deal. Windows 7 users are not likely to be pleased with Microsoft witholding it as an incentive to get gamers to upgrade to its latest operating system. Hopefully some good will still come out of the exclusivity in the form of better ported games. Because the Xbox One supports DX 11.2, I'm hopeful that it will encourage game developers to take advantage of the latest technology and support it on the PC version as well when they do the port of the game.