How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com
Catalina 10.15.3 running decent on my mid 2009 iMac. Gonna max out the RAM to 8GB. 🤗 : r/CatalinaPatcher
apple-history.com / iMac (Late 2009)
How to Upgrade Memory in a Late 2009 21.5-inch or 27-inch iMac - YouTube
iMac Intel 27" Late 2009 EMC 2309 - used original spareparts for Macs
iMac Intel 27" EMC 2309 (Late 2009) Memory Maxxer RAM Upgrade Kit
iMac "Core 2 Duo" 3.06 21.5" (Late 2009) Specs (Late 2009, MB950LL/A*, iMac10,1, A1311, 2308): EveryMac.com
Install memory in an iMac - Apple Support
iMac RAM Memory Installation 2009 2010 2011 21 5" Apple Dollars #13 - YouTube
Install memory in an iMac - Apple Support
Apple iMac A1311 21.5" Desktop - MB950LL/A (October, 2009) for sale online | eBay
iMac | 2.66 GHz Intel i5 | 27 Inch | Late 2009 - Techable.com
Can the Late 2009 27" iMac handle 32GB of RAM? | MacRumors Forums
Install memory in an iMac - Apple Support
iMac (2007-2009) Memory Installation Video - YouTube
A-Tech 16GB (4 x 4GB) PC3-8500 DDR3 1066/1067 MHz RAM for iMac Late 2009 21.5-inch / 27-inch | 204-Pin SODIMM Memory Upgrade Kit at Amazon.com
iMac "Core i5" 2.66 27" (Late 2009) Specs (Late 2009, MB953LL/A, iMac11,1, A1312, 2374): EveryMac.com
Memory Upgrades for Apple iMac 2009 - Up to 32GB
iMac Intel 27" EMC 2309 and 2374 RAM Replacement - iFixit Repair Guide
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com
iMac Intel 20" EMC 2266 (Early 2009) Memory Maxxer RAM Upgrade Kit
apple-history.com / iMac (Late 2009)
iMac (2009) RAM & Storage Upgrades
