Memory RAM 1x 4GB Apple iMac Early 2009 DDR3 1066MHz SO-DIMM | E-OWC8566DDR3S4GB | APPLE \ MEMORY FOR APPLE \ OWC \ APPLE IMAC \ iMac Early 2009 \ iMac 20'' (Early
iMac (Early 2009) | Low End Mac
Crucial - DDR2 - 4 GB: 2 x 2 GB - SO-DIMM 200-pin - 667 MHz / PC2-5300 - CL5 - 1.8 V - unbuffered - non-ECC - for Apple iMac; MacBook (Early 2008, Early 2009, Mid 2007); MacBook Pro - Hunt Office Ireland
Apple iMac 24-inch, Early 2009 - 2.66GHz Core 2 Duo Memory RAM Upgrades - FREE Delivery & Guaranteed Compatible | Mr Memory®
Don't Upgrade The RAM In Your New Apple iMac, Do This Instead
Install memory in an iMac - Apple Support
Install memory in an iMac – Apple Support (UK)
Benefits from RAM upgrade to Late 2009 iMac | MacRumors Forums