The 15-inch Retina MacBook Pro was last updated on July, 24, 2014. Apple has not yet been able to release a refreshed 15-inch model because of Intel's Broadwell delays, but when a new model does launch, we can expect that it will offer many of the same improvements introduced with the 13-inch Retina MacBook Pro.
A refresh will likely include Broadwell processors with better battery life, improved Intel graphics, faster flash storage, and a Force Touch trackpad. The upcoming update is not expected to include a chassis redesign, so the Retina MacBook Pro will continue to be 0.71 inches thick.
The current 15-inch MacBook Air offers a quad-core Crystal Well processor, a variation of the Haswell, with eight hours of battery life, and it includes Intel's Iris Pro HD 5200 graphics. There'a also an option to add an NVIDIA GeForce GT 750M discrete graphics card with 2GB of memory.
Like the 13-inch model, the 15-inch MacBook Pro offers faster 802.11ac Wi-Fi, PCIe-based flash storage that offers 60 percent faster read speeds than the pre-Haswell generation, and dual Thunderbolt 2 ports to allow users to connect multiple displays.
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While the 13-inch Retina MacBook Pro received an update in March of 2015, updates to the 15-inch model are not expected until mid-year when appropriate processors are scheduled to become available.
