There wasn't much doubt that some sort of major update to DirectX was coming after those GDC session abstracts were posted, but now it's official. Microsoft has posted a splash page for DirectX 12 on its MSDN blogs site, and it has created a Twitter account for DX12, as well. The splash page looks like so:
I think the inclusion of Qualcomm is notable, alongside the usual PC graphics contingent of AMD, Intel, and Nvidia. Qualcomm has been making big strides with its Adreno integrated GPUs, but partnering with Microsoft on a cutting-edge graphics API for Windows seems novel. Also, no surprise here, but AMD wasn't kidding when it expressed support for any upcoming DirectX updates.
Based on the session descriptions released last week, we expect the new version of DirectX to have lower CPU overhead and "closer to the metal" access to hardware resources. AMD's Mantle API offers similar perks, but it only works with Radeon graphics hardware. DirectX 12 should be compatible with a wider variety of GPUs. It may also support the Xbox One and mobile devices. There's the Qualcomm's logo, of course, and the descrption for the DirectX session promises information on performance optimzations for PCs, tablets, phones, and consoles.
The folks behind OpenGL are working to lower driver overhead, too, but there doesn't appear to be a new version of the API associated with that effort. Instead, the relevant GDC session will cover "high-level concepts available in today's OpenGL implementations that radically reduce driver overhead."
Cyril will be attending GDC and reporting from Microsoft's 10AM session for us, so we should know more about the specifics of DX12 in a couple of weeks.