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How To: Install RAM in Macbook Pro (Unibody - 2009 to 2011) - YouTube
16 GB RAM Upgrade on MacBook Pro 15" (mid 2012) NON Retina - YouTube
Does the mid-2012 13 MacBook Pro have an M.2 slot that I can use for an Intel Optane memory upgrade? - Quora
MacBook Pro 15" Retina Display Mid 2012 Teardown - iFixit