over at Bit-tech has asked Ageia about the comments John Carmac made about in game physics and that multi-core CPU's are good enough to handle this and as you've already guess, they don't agree with him.
They've had a chat with Michael Steele and Daniel Forster from Ageia about the future of game physics and about GRAW2. But the most interesting part of the article is Ageia's response to why a multi-core CPU isn't good enough.
“Carmack has said this type of thing before though and I challenge you to dig a little and see what Carmack said about 3D graphics when they first came out – he said it wasn’t going to happen..."
it continues "there are guys who are developing games who say they think they can program it themselves and do it without the hardware and we say; ‘Really? Show us."
There are also some interesting information about the physics engine in Crysis and you can read the full article here