Thanks Lou.Nvidia releases 2 drivers for their GPUs. The Web Driver to drive the card in the Mac environment and the CUDA Driver for folks that utilize Cuda. The Web Drivers are specific for each OS point release. The Cuda Driver usually covers a couple of OSs. The latest CUDA Driver is 8.0.51 and is available here:
http://www.nvidia.com/object/macosx-cuda-8.0.51-driver.html
And works with 10.11.x and 10.12.x
And no, the CUDA driver is not needed if you are not using anything that uses CUDA.
Lou