Apple iMac 27-inch (July 2010) review: Apple iMac 27-inch (July 2010) - CNET
NEMIX RAM 16GB (2x8GB 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
32.0GB OWC Memory Upgrade Kit For 2010-2011 Apple iMac
Amazon.com: Timetec 16GB KIT(2x8GB) Compatible for Apple DDR3 1333MHz PC3-10600 CL9 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) MAC RAM Upgrade :
iMac RAM upgrade: Here's an affordable way to improve multitasking - CNET
Install memory in an iMac - Apple Support
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com
Install memory in an iMac - Apple Support
OWC Performance Upgrades for iMac 2010
16GB -2x8GB Memory Ram Upgrade for 27" Apple iMac-11.3 Core i5 3.6GHz Mid 2010 | eBay
How to Upgrade Memory in a 21.5-inch or 27-inch iMac (Mid 2010) - YouTube