Memory Upgrades for iMac 27-Inch (2012 - Mid 2015)
CMS 32GB (4X8GB) DDR3 12800 1600MHz Non ECC SODIMM Memory Ram Upgrade Compatible with Apple® iMac Core I7 3.4 27-Inch (Late 2012) - A6 at Amazon.com
iMac RAM upgrade: Here's an affordable way to improve multitasking - CNET
Memory Upgrades for iMac 27-Inch (2012 - Mid 2015)
How to Upgrade/Install Memory in a 21.5-inch iMac (Late 2012– Mid 2014) iMac14,1 iMac14,3 - YouTube
Install memory in an iMac - Apple Support
Can you upgrade the RAM in the 27-inch iMac? | iMore
How to Upgrade/Install Memory in a 21.5-inch iMac (Late 2012– Mid 2014) iMac14,1 iMac14,3 - YouTube
OWC 8GB (2 x 4GB) PC12800 DDR3L 1600MHz SO-DIMMs Memory Compatible with 2011-2015 iMac, 2011-12 Mac Mini, and 2011-2012 MacBook Pro (Non-Retina Display) Models (OWC1600DDR3S08S) at Amazon.com
Timetec 16GB KIT(2x8GB) Compatible for Apple DDR3L 1600MHz for Mac Book Pro(Early/Late 2011,Mid 2012), iMac(Mid 2011,Late 2012,Early/Late 2013,Late 2014,Mid 2015), Mac Mini(Mid 2011,Late 2012) MAC RAM at Amazon.com
Install memory in an iMac - Apple Support
Apple's 2012 iMac: Ready for its close-up (pictures) - CNET