Maxwell 4 comes with a GPU rendering and FIRE option. Video Subtitles available.
For GPU rendering, Nvidia graphics cards with CUDA support are required, and Apple does not sell computers which include these at this time. Therefore Maxwell GPU rendering is not currently supported on Mac OS.
If you do have an older Mac model with an nVidia card, we cannot guarantee you a great experience, because those cards are obsolete and have not been tested. Also, while GPU connections are possible through third party Thunderbolt devices, these have not been thoroughly tested and we cannot guarantee stability.
Should Apple include graphics cards appropriate for GPU rendering in the future, we will likely support these.