I'm a little late with this one, but perhaps you've seen this interview with an Ubisoft Splinter Cell developer. In the interview, he states that "the PS3 can't handle AI nearly as well as the 360."
First off, let me state that I am in no way a Sony fanboy. I don't even own a current generation console. That said, this statement is completely devoid of meaning.
You know what AI is? A plain old algorithm. A search process, selecting a rule from a rule base, or running through a pattern matcher. Saying the PS3 cannot do AI is like saying it cannot do sorting or print the first ten integers.
What some people are referring to to support the Ubisoft developer's argument is the PS3's relatively poor branch prediction ability. The argument then being, since most game AI is simply a giant switch statement, performance will suffer.
My response to this is, developer ignorance of AI is not a good excuse. If you think AI amounts to a giant switch statement then you need to go read a book, or a modern survey of AI planning.