Well:

1. They kept existing designs, since even Jobs wasn't so crazy as to demand a complete re-architecture of existing laptop models on a whim; plus they probably also had contractual obligations/pre-purchase arrangements

2. They switched to nvidia, but from everything I know they also hated working with nvidia (IIRC Jobs accused nvidia of stealing Pixar tech)

3. AMD is a different company than ATI (technically), and Apple of that era was different than the Steve Jobs temper tantrum era.

But yes, relevant details.