- The bottom cover no longer twists off like the old model — a first sign that it's hard to get inside and fiddle. Instead, you need to undo some Torx screws.
- A lot of the basic internals are revamped: its Airport card has grown up into a fully developed PCIe card, for instance, and there's even a "promising mounting point for a blade-style PCIe SSD."
- The rumours were true: the RAM is soldered to the logic board. No upgrading here.
- There's also only one SATA port, too, which means you can't add a second hard drive. Though you can at least swap out the existing one, if you don't mind voiding the warranty.
- Elsewhere, much remains the same—the power supply, for example, is the same as the one in the 2012 (and 2011!) model.
So, really, we're looking at a computer whose basic hardware — the processor, RAM and the like — has been upgraded, in a harder-to-tweak package. No surprise, really. [iFixit]