MacOS Rumors posts a hint about an Apple/NVidia partnership:
- Apple's work with nVIDIA on a HyperTransport-enabled motherboard chipset may include the functionality included in nVIDIA's latest nForce2 mobo chipset - notably 3D Positional Audio that would support true digital surround sound for the first time in Apple's history....
Apple/NVidia and specifically NForce 2 rumors have been floating around since July.