According to a leaked Apple repair guide for the 15-inch Retina MacBook Pro, many of the internal parts including the SSD, I/O Board, Logic Board and even the bottom case have been updated to new parts. Although it isn’t clear yet how the updated parts were changed (aside from the obvious CPU speed), it reminds us of a Foxconn leak that was released in October 2012 and mentioned the following:
1. The rmbp in production line D2 is identified as defected products as in terms of thermal heating and screen ghosting. P/S: Apple is not going to re-launch the 15” rmbp. Just that Apple will improve on the production technique in D2 line. Apple will launch the 13” rmbp. Ghosting and thermal issues will be fixed but internals and design will be similar to 15” rmbp.
The new upgrade also seems to be a bigger change than the previous generation jump, leaving potential customers much to look forward to.