iMac 21.5" Mid 2011 How To Change/Upgrade Your Ram For Better Performance 2014 - YouTube
A-Tech 16GB (2x8GB) RAM for Apple MacBook Pro (Early/Late 2011), iMac (Mid 2010 27 inch 4-Core, Mid 2011 21.5/27 inch), Mac Mini (Mid 2011) | DDR3 1333MHz PC3-10600 204-Pin SODIMM Memory Upgrade Kit at Amazon.com
21.5” mid-2011 iMac wires? Finally trying to upgrade my RAM and these wires are blocking the slot — did get an iMac with poor build quality? What can I do? : r/mac
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com
How to Upgrade Memory in a Late 2009 21.5-inch or 27-inch iMac - YouTube
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