After we saw the performance gains of using multi-threaded rendering in DirectX 12 for the initial Tides of Vengeance update, we worked together with Microsoft and our hardware vendors to bring similar performance gains to our Windows 7 users. We are pleased to announce that with today’s content update, World of Warcraft will now support DirectX 12 on Windows 7. This allows our Windows 7 users to take advantage of the performance benefit of using DirectX 12, which was previously only available to our Windows 10 users.
Windows 7 users will need to make sure they have the latest graphics drivers to use DirectX 12. If your GPU supports DirectX 12 on Windows 7, you may enable it by selecting it in the Advanced System settings, under "Graphics API".