[moyta]

Yeah, given a sizable power budget and the right benchmarks, Nvidia can outperform Radeon cards, but Apple has an exisistung relationship with AMD and there is not a compelling performance case to switch to Nvidia.

Plus with Supercomputing Clusters eating up most of Nvidia's production, Apple is not guaranteed to get the quantity & bin of GPUs they need on their schedule. This is the same reason why Apple didn't release any fusion based Macbooks, the bin of chip they wanted was not available in the quantity Apple needed by launch.