NEMIX RAM 32GB (4x8GB Upgrade) DDR3-1333 PC3-10600 204-Pin SODIMM Memory for Apple MacBook Pro Early/Late 2011, iMac Mid 2010 27 inch 4-Core, iMac Mid 2011 21.5/27” , Mac Mini Mid 2011 at Amazon.com
iMac RAM upgrade: Here's an affordable way to improve multitasking - CNET
How to Upgrade iMac RAM: 2012-2022: EveryMac.com
OWC 32GB (4 x 8GB) PC12800 DDR3L 1600MHz SO-DIMMs Memory Compatible with 2011-2015 iMac Models (OWC1600DDR3S32S) at Amazon.com