Mike Wuerthele
According to Apple documentation, the old bandwidth limitation on the 13-inch MacBook Pro is a thing of the past.
Apple's shift to a processor with more PCI-e channels is responsible for an increase in total bandwidth to the new 13-inch MacBook Pro. The previous dual-core i5-7360U processor in the 13-inch MacBook Pro with Touch Bar had 12 PCI-e lanes for communication.
The new model has the i5-8259U processor, with 16 PCI-e lanes. More PCI-e lanes allow for both Thunderbolt 3 controllers of the machine to have full data path width, and as such, full speed.
Apple detailed the bandwidth limitation on a document covering Thunderbolt 3 connectivity after the 2016 MacBook Pro was released. Specifically, the two ports on the older notebook's right hand side provide full Thunderbolt 3 functionality, but have reduced bandwidth, while the left pair retains full PCIe throughput.
For this reason, Apple recommended connecting high performance peripherals like fast Thunderbolt 3 RAID arrays via the left-hand ports. The 15-inch MacBook Pro model has always supported full PCI-e bandwidth on each of its four Thunderbolt 3 ports.
Malcolm Owen
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16 Comments
hmm, seems the 13 inch is the pick of this update.
Don’t care.
No parallel printer port, no deal.
Maybe in 2019, Cook will finally deliver a Mac laptop with the built-in rotisserie we’ve been screaming for.
MFW I realize I've been plugging my 5K display into the wrong ports...
Good! As far I know Apple doesn't make it easy to know which ports had full speed. Maybe we'd put to memory which ports could support a 5K display or other peripherals, and why, but the typical user shouldn't. Luckily, this probably wan't ever a major issue.