While testing the 2016 MacBook Pro, a consistent pattern of declining performance was observed. For example, with 10 iterations of of the Photoshop sharpening test, the 2016 MacBook Pro declined in performance by 23%. No such decline was seen on the iMac 5K or 2013 Mac Pro.
This differential helps explain why the 2016 MacBook Pro is slower than the 2013 MacBook Pro on the Lightroom import test.
This finding may be of keen interest to anyone processing video or importing into Lightroom or any task that incurs a sustained load.