Actually it's kind of black magic to know which cards supports or does not support CI.
You can find a partial list on the Apple web site, here:
It seems that some other cards are supported. Also I think (but I might be wrong) that some effects may be supported by some cards (depending of the complexity of the shader) while some others not. When the cards do not support CI, it falls down to altivec optimized code which is bad (but not as bad as non-vectorized CPU code).
It seems that the best is to give a try on your machine. there are several freewares out there that allow you to test CI filters.