Apple dropped Intel’s integrated Iris Pro graphics in favor of dedicated AMD graphics across its entire new 15-inch MacBook Pro lineup, resulting in performance improvements over previous models. Perhaps more interestingly, the switch to AMD provides expanded external display support that desktop users have patiently waited for.
As Andrew Cunningham at Ars Technica explains, AMD’s Polaris-based Radeon Pro 450, Radeon Pro 455, and built-to-order Radeon Pro 460 GPUs in the new 15-inch MacBook Pro support up to six displays, whereas Intel’s integrated GPUs affixed to the logic board can drive a total of three displays.
The expanded support enables the new MacBook Pro to drive two of Apple and LG’s new UltraFine 5K displays at 60Hz simultaneously. Intel’s GPUs can’t because, due to bandwidth limitations of the DisplayPort 1.2 spec, the two 5K displays technically function as four displays. This method is known as Multi-Stream Transport (
