Amazon.com: Timetec 8GB KIT(2x4GB) Compatible for Apple DDR3 1333MHz PC3-10600 for Mac Book Pro (Early/Late 2011 13/15/17 inch), iMac (Mid 2010, Mid/Late 2011 21.5/27 inch), Mac Mini(Mid 2011) RAM Upgrade : Electronics
CMS 16GB (4X4GB) DDR3 10600 1333MHZ Non ECC SODIMM Memory Ram Upgrade Compatible with Apple® iMac Core I3 3.06 21.5-Inch (Mid-2010) - A28 at Amazon.com
Install memory in an iMac - Apple Support
iMac (mid 2010 - early 2019) SSD & Arbeitsspeicher/RAM Upgrade/Aufrüstung | iMac (2010 - 2019) | Mac Upgrade/Aufrüstung | Tronicspot
Is it worth it to upgrade RAM on Mid 2010 21.5 iMac? | MacRumors Forums
Install memory in an iMac - Apple Support
Install memory in an iMac - Apple Support
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
RAM upgrade considerations for iMac systems - CNET