Concerning your reverts on WDDM The Microsoft MSDN article clearly states Windows 8 1 Preview introduces version 1 3 of the Windows Display Driver Model WDDM and The following functionality has been added in Direct3D 11 2 which is included with Windows 8 1 Preview Windows RT 8 1 Preview and Windows Server 2012 R2 Preview along with all the features that I supposedly claimed WDDM1 3 is in fact used in Windows 8 1 Preview you can verify it by yourself