ATI's Xbox 360 GPU details

If I have read it once, I have read it a thousand times, “The Xbox 360 is just ATI’s next generation (fill in favorite code name here) GPU.” The simple answer to that is, “No it is not.” While most modern GPUs share many architectural similarities, Bob Feldstein and Chris Evenden of ATI went out of their way to explain to me, no matter how hard I tried to convince them otherwise, that the Xbox 360 GPU is very much an original creation. While some will try to tell you that is it simply a souped up DirectX 9 GPU, you might be interested to learn that the only API spec that the Xbox 360 hardware meets is its own API. That is correct, the Xbox 360 GPU only meets it own Xbox 360 API specifications.