Authorized Apple dealer B&H Photo loaned MPG the Apple 15.4" MacBook Pro Retina (Mid 2015), 2.8GHz / Radeon R9 M370X / 16GB / 1TB, the configuration MPG recommends for power users, photographers, videographers, etc. Save money on AppleCare too.
This test is as real world as it gets, one that your author does day in and day out for generating lens rendering aperture series.
Thus it is of great practical value to ask whether the combination of faster SSD, slightly faster CPU and faster GPU in the 2015 MacBook Pro Retina could improve upon the late 2013 MacBook Pro Retina.
Deciding whether to upgrade is a combination of performance, screen technology, battery life, and other features; these all need to be weighed as factors as per real value. Since the 2015 MacBook Pro Retina model tested is an about $3100 configuration, trading up may at least start with a realistic assessment of performance differences for daily tasks—always a superior approach to benchmarks.