Isn't there some sort of lawsuit between Intel and nVidia? I know Apple has been phasing them out for a while now..
What is CUDA??? I should know this. Will an nVidia card work in these new Mac Pros?
CUDA is a programming environment that allows to run code on the graphic card.
If you have a program that can be parallelized in many processes, using it on a graphic card (that has hundreds of cores) can speed it up by a factor of 200 or more.
There are alternatives to CUDA that work cross-cards but not as advanced as CUDA. I just don't get why apple would slam the door at all these developers.