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Two of these models were released this year, one was released in early 2011 and the other in late 2011. There are very few differences, but a notable one is that the later model came with either a 2.2GHz or 2.4 GHz dual-core Intel processor, and the earlier model had either a 2.3GHz or 2.7GHz dual-core Intel processor.Software Compatibility: Up to macOS High Sierra 10.13.6.Two of these models were released this year, one was released in early 2011 and the other in late 2011. There are very few differences, but a notable one is that the later model came with a 2.4 GHz dual-core Intel processor, and the earlier model had a 2.2GHz dual-core Intel processor.This model is also significantly thinner than its counterpart.
WHICH CHARGER FOR MACBOOK AIR 11 INCH EARLY 2011 VERSION PRO
This MacBook Pro includes a Retina display, which differentiates it from the other 2012 15-inch MacBook Pro. This model is also significantly thinner than the earlier model. This MacBook Pro includes a Retina display, which differentiates it from the early 2012 13-inch MacBook Pro.
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MacBook Pro (13-inch, Two & Four Thunderbolt Ports) Software Compatibility: This and all models since late 2013 can run the latest macOS.
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This information is enough for most users, but for user guides and part numbers, you'll need to reference Apple's MacBook Pro page.
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