OpenGL on OSX has also been outperformed by OpenGL on Windows in recent years. Their support for it over the past few years has been terrible, so it's not a very high bar. I kind of wonder if they borrowed from AMD and Mantle on this one. Interestingly Khronos still lists Apple as a working group participant for Vulkan (bottom of the page), which was announced under a different name just a bit before Metal, although they only started using the name Vulkan this year.
6/11/15 at 1:40am