Codeplay Director Andrew Richards says, “Overall, Cg is not a generic language for graphics programming; it is a language for NVIDIA®’s current generation of graphics card. It has a different set of goals from what’s required to design computer graphics at the heart of the successful computer games of tomorrow.”
Codeplay believes that Cg is inadequate for some current, and more future, ‘GPU’s. Most importantly, standard rendering code needs to move onto graphics processors, and Cg is not sufficiently flexible for this type of code.
The above quote is from Codeplay's Website. They don't seem to think its such a good idea.
Here is the ink to the whole article:
CODEPLAY RESPONDS TO NVIDIA®'s 'CG'
