Apple - Are all the ports on 2016 MacBook Pro 13" the same speed?

As it turns out, there is a support document published by Apple that directly answers my question:

Late-2016 MacBook Pro models vary slightly in the data speeds they provide to each Thunderbolt 3 port.

MacBook Pro (15-inch, Late 2016) delivers full Thunderbolt 3 performance on all four ports.

MacBook Pro (13-inch, Late 2016, Four Thunderbolt 3 Ports) supports Thunderbolt 3 at full performance using the two left-hand ports. The two right-hand ports deliver Thunderbolt 3 functionality, but have reduced PCI Express bandwidth.

MacBook Pro (13-inch, Late 2016, Two Thunderbolt 3 Ports) delivers full Thunderbolt 3 performance on both ports.

Therefore based on this, I will use the left-hand ports for my high bandwidth peripherals.

Mactracker specifies: 4 - up to 40 Gbps

Apple Support Document specifies even further:

Four Thunderbolt 3 (USB-C) ports with support for:

• Charging
• DisplayPort
• Thunderbolt (up to 40 Gbps)
• USB 3.1 Gen 2 (up to 10 Gbps)

The key phrase here is up to. 40 Gbps is the theoretical maximum the MBP T-Bolt ports can provide, but most likely that speed is never fully attainable, nor sustainable, under normal usage.

Your milage may vary.