Upgrading 27" iMac (2011) To 32GB Of RAM - YouTube
Install memory in an iMac - Apple Support
Apple Launching Pilot Program Allowing Repairs of Soon-to-Be Vintage Mid 2011 iMac in United States - MacRumors
Apple iMac 2.7Ghz i5-2500S 27-Inch (Mid-2011) *NO HDD/RAM* – MSU Surplus Store
Timetec 32GB KIT(4x8GB) Compatible for Apple DDR3L 1600MHz PC3L-12800 CL11 for iMac (Mid 2011, Late 2012, Late 2013, Late 2014 Retina 5K, Mid 2015 Retina 5K) SODIMM Memory Module MAC RAM Upgrade at Amazon.com