CMS 4GB (1X4GB) DDR2 6400 800MHZ Non ECC SODIMM Memory Ram Upgrade Compatible with Apple® iMac Core 2 Duo 2.4 20-Inch Early 2008 - A42 at Amazon.com
4GB Kit (2GBX2) DDR2 800MHz RAM Memory Upgrade for Apple iMac Core 2 Duo 20-inch (Early 2008) (PARTS-QUICK) - Walmart.com
iMac Memory for Model 8.1 | DDR2-800MHz |4GB | MacMemory.com
2008 iMac Ram upgrade and OS update! - YouTube
Apple iMac "Core 2 Duo" 2.66 20-Inch (Early 2008) , 320 GB Hard Drive, 2 GB RAM - Imagine41
Apple iMac 20-inch 2.4GHz Core 2 Duo (Early 2008) MB323LL/A 2 | mac of all trades
Memory Upgrades for Apple iMac 2008 - Up to 6GB
Install memory in an iMac - Apple Support
Timetec Hynix IC 8GB KIT(2x4GB) Compatible for Apple DDR3 1067MHz/1066MHz PC3-8500 SODIMM RAM Upgrade for Late 2008, Early/Mid/Late 2009, Mid 2010 MacBook, MacBook Pro, iMac, Mac Mini (8GB KIT(2x4GB)) - Walmart.com
Memory Upgrades for 2019-2020 iMac 27-Inch - Up to 128GB