We got asked about this on our Facebook page and it's a great question so we are sharing the answer here as well.
Windows 8 will run on a wide range of form factors, from super-light, low-power tablets to high-end, high-power gaming rigs. Microsoft is recommending that game developers use the DirectX 11 API if they intend to support both Windows 8 and Windows RT, especially if they are developing Metro style apps."You have written on your website '3DMark for Windows is the world's first unified graphics benchmark able to test all DirectX 9, DirectX 10 and DirectX 11', if i'm not mistaken Unigine's Heaven Benchmark as been had support for these since October 2009. they've also included OpenGL 4.0 as of recently. So how is 3DMark the first?"
Other benchmarks, including ours, typically use legacy APIs like DirectX 9 and DirectX 10 to support older hardware, but the next 3DMark will always use DirectX 11 regardless of the target hardware.
The next 3DMark will render to DirectX 9 and DirectX 10 hardware by using a feature of the DirectX 11 API that Microsoft calls 'feature levels'. While this will allow the benchmark to run on older hardware, its main purpose is to enable the benchmark to test the new class of DirectX 9 and DirectX 10 hardware used in new devices such as lightweight tablets and ultrabooks.
These feature levels are also good for gamers as many DirectX 9 functions are faster and more efficient when called through the DirectX 11 API compared to the legacy DirectX 9 API. Feature levels are an important part of how Windows 8 and Windows RT handle graphics, especially on Windows RT tablets and devices. There are more details about feature levels on the Microsoft developer page.
So to answer the question, 3DMark for Windows is different from Heaven because it will be the first benchmark for testing DirectX 9, DirectX 10 and DirectX 11 hardware through the DirectX 11 API.