I downloaded and ran the MS DirectX End-User Runtimes (June 2010) installer for all three versions of DX, 9, 10, and 11. Now my DX11 fps is higher than before. In the DX11 version I was getting lower FPS than the DX9 version. I wonder if the guys reporting fantastic FPS higher than in the DX9 version are also running Win10. It is worth a shot if you are getting lower FPS in the DX11 version than the DX9 version.
My OS is Win7 Pro 64bit.