Timetec 8GB KIT(2x4GB) Compatible for Apple DDR3 1067MHz / 1066MHz PC3-8500 CL7 for Mac Book,
20″ iMac (Early 2008) | Low End Mac
Install memory in an iMac - Apple Support
4GB -2x2GB Memory Ram Upgrade 20" Apple iMac-8.1 2.4GHz Core 2 Duo Early 2008 | eBay
Timetec 8GB KIT(2x4GB) Compatible for Apple DDR3 1067MHz / 1066MHz PC3-8500 CL7 for Mac Book, Mac Book Pro, iMac, Mac Mini (Late 2008, Early/Mid/Late 2009, Mid 2010) SODIMM Memory MAC RAM Upgrade
How to Upgrade/Install Memory in a 21.5-inch iMac (Late 2012– Mid 2014) iMac14,1 iMac14,3 - YouTube