The MacBook Pro "Core i7" 3.1 13-Inch (Early 2015 Retina Display) originally was a "configure-to-order" configuration for both the MacBook Pro "Core i5" 2.7 13-Inch (Early 2015 Retina Display) and MacBook Pro "Core i5" 2.9 13-Inch (Early 2015 Retina Display), but also is documented as a separate model for reader convenience. Starting on October 27, 2016, it only is a CTO option for the MacBook Pro "Core i5" 2.7 13-Inch (Early 2015 Retina Display). The processor (and the corresponding larger level 3 cache), are the only substantial differences between this model and its stock compatriots.