Nvidia Cards Unable to Use DirectX12 on Windows 7 since 8.3
Due to a compatibility issue with windows 7, World of Warcraft, and the latest Nvidia driver builds as of this writing, DirectX12 has been temporarily disabled on Turing/Pascal graphics cards for players on Windows 7. If you would like to use DirectX 12 on Windows 7, you will need to roll back to the last known stable driver (441.41) until a future driver is released which fixes the bug.