Touch Bar-equipped MacBook Pros sport new AMD GPUs, can drive dual 5K displays

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Date: Tuesday, November 15th, 2016, 05:27
Category: Hardware, Intel, MacBook Pro, News, Processors, Thunderbolt

lg-ultrafine-5k-macbook-pro

Apple apparently dropped a killer GPU into the 2016 Touch Bar-equipped 15-inch MacBook Pro and it shows.

The company, which switched from Intel’s integrated Iris Pro graphics in favor of dedicated AMD graphics, has opted for AMD’s Polaris-based Radeon Pro 450, Radeon Pro 455, and build-to-order Radeon Pro 460 GPUs in the new 15-inch notebooks. The GPUs 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 (MST).


Over on Are Technica, the current analysis offered the following comments:

When you hook one of LG’s 5K monitors to one of the new MacBook Pros, what you’re actually seeing on the screen is two pictures stitched together to make a single seamless image. This is because the version of the DisplayPort spec supported by Intel’s GPUs and almost all monitors these days—version 1.2—doesn’t have enough bandwidth to drive a 5K display at 60Hz all by itself. […] Apple is actually pushing two DisplayPort 1.2 streams to the monitor over the single Thunderbolt 3 cable.

There’s nothing wrong with this method, except that it cuts down on the number of external displays your computer can support. Intel’s integrated GPUs can drive a total of three displays, but you use up two of those three streams to drive one 5K monitor and one of them to drive the laptop’s internal display. AMD’s GPUs support up to six displays, so you can use two of those connections for one 5K monitor, two of them for the other 5K monitor, one for the laptop’s internal display, and still have one left over for yet another monitor if you really wanted to use one.

While Apple could have used Nvidia’s faster Pascal-based GPUs, which presently support DisplayPort 1.3, the Thunderbolt 3 and most monitors don’t fully support the faster Pascal protocol. In the meantime, Nvidia’s GPUs can only drive up to three displays beyond the main MacBook Pro screen, the bandwidth not being sufficient yet to drive dual 5K displays over MST.

It’s felt that the new MacBook Pros will have more accessibility once the DisplayPort 1.3 protocol becomes more common on monitor hardware. Apple’s current and next-gen notebooks will be able to drive two 5K screens plus a laptop’s internal screen using just three DisplayPort streams instead of five.

Pretty cool for now and you can read the full breakdown and test results via the Ars Technica link.

Via MacRumors and Ars Technica

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