iMac 20-inch (Mid-2009) Core 2 Duo 2GHz - HDD 160 GB - 4GB | Back Market
iMac (Early 2009) - Technical Specifications
iMac 2009-2011 – iRevive
Apple iMac A1311 21.5" Desktop - MB950LL/A (October, 2009) for sale online | eBay
iMac (27-inch, Late 2009) 500GB SSD Upgrade - NiwTech
iMac Early 2009 24" Upgrade Kit - Real Mac Mods
apple-history.com / iMac (Mid 2009)
Upgrade the Hard Drive in 2009 and Later iMacs
How to Upgrade the RAM in Your iMac
Is it worth upgrading my ram on a Late 2009 iMac? New iMacs/MacBooks are very pricey. It's currently running on 4GB of RAM & it has a 3.06GHz Intel Core Duo Processor. :
Upgrading an iMac GPU for METAL Support! Late 2009 – Mid 2011 Models - YouTube
Apple iMac Core 2 Duo Computers | MB950LL/A | Discount-Computer.com
iMac Intel 20" EMC 2266 Teardown - iFixit
How to replace HDD/SSD in iMac Mid 2007/Early 2008/Early 2009/Mid 2009 | Mac Cheat Sheet