A-Tech 32GB (4x8GB) RAM for Apple iMac (Mid 2010 27 inch 4-Core, Mid 2011 21.5/27 inch) | DDR3 1333MHz PC3-10600 204-Pin SODIMM Memory Upgrade Kit at Amazon.com
A-Tech 16GB Kit (2x8GB) DDR3 1066MHz / 1067MHz PC3-8500 SODIMM RAM for Apple MacBook (13 inch, Mid 2010), MacBook Pro (13 inch, Mid 2010), iMac (27 inch, Late 2009), Mac Mini (Mid 2010) at Amazon.com
Amazon.com: Timetec 32GB KIT(4x8GB) Compatible for Apple DDR3 1333MHz PC3-10600 CL9 for iMac (Mid 2010 27 inch, Mid 2011 21.5/27 inch) SODIMM Memory Module MAC RAM Upgrade for iMac 11,3 / iMac 12,1 / iMac 12, 2 : Electronics
21.5- and 27-inch iMacs (Mid 2010) | Macworld
Just scored this 2010 iMac 21” i3 for $27!!! (I have a few upgrade question) : r/mac