Entry level models have a single integrated graphics (IG) processor, and higher-end models offer dual graphics (DG) processors. Internally, the Mid 2015 model has a highter capacity battery, a new 'Force Touch' trackpad, and faster flash storage. In May 2015 Apple introduced a new 15' MacBook Pro with Retina display that is externally identical to the 'Mid 2014' model by dimensions, weight, and 2880x1800 display resolution.
