Late 2016 MacBook Pro Capped At 16GB RAM Because Batteries
Apple's MacBooks, be they the Pro, normal, or Air variety, have always been praised for their slim and light designs, relatively speaking. But as computing hardware gets more powerful, something will eventually have to give. In this year's case, apparently that is the MacBook Pro's RAM that was the scapegoat. Apple has taken flak for the laptop's 16 GB RAM limit, which power users have analyzed and criticized to no end. This has lead Apple SVP for Worldwide Marketing Phil Schiller to take the mic to defend the decision, which basically boils down to compromising for better battery life.
In the latest round of apologetics, Schiller clarifies that the MacBook Pro actually uses a "very fast" RAM technology running at 2133 MHz. This was later revealed to be a special low power type of DDR3 memory called LPDDR3E. This particular RAM, unfortunately, is capped at 16 GB, hence the similar cap in the latest MacBook Pro.
So why not go with a more current DDR type? That would be DDR4 in this case, which is a desktop-class RAM technology. Such an option would, however, have two negative effects on the MacBook. The first is that DDR4's low power version isn't yet supported by the Intel Skylake processors in the MacBook. A full DDR4 implementation would therefore sap the battery faster.
It doesn't end there. Using DDR4 would have required Apple to change the design of the MacBook Pro's logic board, which would mean rearranging some components and downsizing others. And, as yo might have guessed by now, it will be the battery that will take the hit for that.
So, in a nutshell, the 16 GB RAM max is a compromise made by Apple to keep battery consumption low and, therefore, keep the MacBook Pro running as long as possible. Most normal users will probably not mind, but there's a reason there's a "Pro" in the MacBook Pro's name. This is the class of Apple's notebooks that are used by developers and multimedia workers, who would definitely benefit from 32 GB of RAM. Coincidentally, they are also the ones making the loudest noise over this MacBook Pro kink.
SOURCE: MacDaddy