A-Tech 8GB RAM for Apple MacBook Pro (Mid 2012), iMac (Late 2012, Early/Late 2013, Late 2014, Mid 2015), Mac Mini (Late 2012) | DDR3 1600MHz PC3-12800 SODIMM 204-Pin Memory Upgrade at Amazon.com
SSD Upgrades for Apple iMac 27-Inch Late 2013 - 2019
Install memory in an iMac - Apple Support
Apple iMac 27" Late 2013 A1419 Logic Board i5 3.2GHz 775M 1GB 661-7516 | MacKing
How to Upgrade Memory in a 27-inch iMac (Late 2012-2013) iMac13,2 and iMac14,2 - YouTube