This article informs you why your Thunderbolt 3 device may experience slow performance when connected with the late-2016 MacBook Pro.
All Thunderbolt 3 ports available on the new MacBook Pro (13-inch, Late 2016, Four Thunderbolt 3 Ports) support Thunderbolt 3 devices, although the two ports located on the right-hand side have reduced bandwidth.
In order to take advantage of full Thunderbolt 3 performance, it’s recommended to connect higher performance devices to ports located on the left-hand side.
Only the 13-inch MacBook Pro from late 2016 with four Thunderbolt 3 ports has this variance. Other recently released MacBook Pro models provide equal performance to all Thunderbolt 3 ports.