I use Blender with my iMac Late 2012 and I have the graphics card NVIDIA GeForce GTX 660M. In the internet it says, that this graphics card has CUDA but however I cannot change the 'Compute Device' in my User Preferences. Anyone an idea?

I use Blender with my iMac Late 2012 and I have the graphics card NVIDIA GeForce GTX 660M. In the internet it says, that this graphics card has CUDA but however I cannot change the 'Compute Device' in my User Preferences. Anyone an idea?
