I have tested DX12 versus DX11 on AMD Adrenalin 19.3.3 Driver on Windows 7 with World of Warcraft running on AMD GPU.
Setting it up is easy, you kjust need to patch Windows 7 SP2 to the latest available updates and make sure you are running Patch 8.1.5. of World of Warcraft. Then just select DirectX 12 option on the System -> Advanced -> Graphice API menu.
Here are a couple of videos to show performance comparison.
Video 1: World of Warcraft running on AMD GPU with DX12 interface on Windows 7 - YouTube
I selected one particular scene @ 4K Resolution with the graphics settings in the videos and ran separate tests.
I get the following averages.
DX11 36.1 FPS.
DX12 44.3 FPS.
That is a reasonable performance uplift of ~ 22.7%.
Note I had turned on the Radeon Overlay in the videos but, it did not record in ReLive properly on either DX11 or DX12.
I used the World of Warcraft FPS counter (enable using CTRL+R) in game to look at the FPS.
Motherboard: ASUS Z87 Deluxe.
GPU: XFX R9 Nano running on PCIe 3.0x4 interface.
RAM: 32GB DDR3.
HDD: Seagate 1TB SSHD.
Any news of other DX12 titles on Windows that will be available to test soon?