One of many articles. AMD confirmed it will be supported on existing GCN cards (HD 7000, 8000, and R series), and it will compete against Mantle, though one has to expect Mantle to give better results with AMD cards, but we will have to wait for the benchmarks.
That answers the question about Windows 7 support for DirectX, kinda.
After Microsoft's announcement this morning, a short question and answer period followed. Some questions, such as will DirectX 12, a just-announced and prototype API that's still a year away, be supported on Microsoft's soon-to-be-retired Windows XP operating system, were a foolish waste of everybody's time. The follow-up question by a more informed attendee was much more relevant: will DirectX 12 be supported on Windows 7? The answer lacked any hint of positivity, making even a dismissive parent's "maybe" seem very promising.
Explaining that Windows 7 support will be addressed at an appropriate time in the future is either avoidance marketing speak for "not supported", or it's a crafty attempt to build suspense that Microsoft later exploits to show how benevolent they are when support is confirmed. My money is on Windows 8 support by way of timed update, and native support in Microsoft Windows 9. As for the masses who still play games with Windows 7, if you want DirectX 12 support you had better start making a lot of noise right now or get ready for an OS upgrade.</end quote></div>
The good thing is, if DirectX 12 doesn't support Windows 7, Mantle will, which will give AMD an edge.