How to Upgrade/Install Memory in a 21.5-inch iMac (Late 2012– Mid 2014) iMac14,1 iMac14,3 - YouTube
16GB KIT 2X 8GB for Apple iMac 2.7GHz 21.5" Late 2013 2.93GHz 27" Late
Install memory in an iMac - Apple Support
Memory Upgrades for iMac 21.5-Inch 2012 - Late 2013
Memory Upgrades for iMac 21.5-Inch 2012 - Late 2013
I got a FREE 2013 iMac 21.5 with internal upgrades including Samsung evo ssd and 16gigs of ram. Then used open legacy patcher to install Mac OS Venture 13.5 beta. : r/OSXBeta
Late 2013 iMac review: Faster than before, but the gains over previous models are modest | Macworld