OWC DIY Kit for 2012 - 2019 21.5" iMac's factory... at MacSales.com
Some Users Report macOS High Sierra Gives Old Macs Better Performance - The Mac Observer
See which Macs will -- and won't -- work with MacOS - CNET
Late 2009 iMac - Should You Upgrade to High Sierra? | All Apple All Day
Apple iMac 21.5" All In One Computer Core i3 3.1GHz 4GB 250GB Mac OSX Sierra
See which Macs will -- and won't -- work with MacOS - CNET
Identify your iMac model - Apple Support
Apple Imac 20" Early 2009 A1224 Intel Core 2 2.66ghz 4gb Ram High Sierra & More | eBay
iMac 21.5" (A1311) • Beetstech
USE MY OLD IMAC AS SECONDARY DISPLAY - Apple Community
Installing MacOS Sierra on an unsupported Mac (2009 MacBook Pro 5,4) - YouTube
Retro Review: 2009 Mac Pro in 2022 | iMore
macOS Sierra | Low End Mac
Apple iMac A1224 Mid 2009 20in 2.26GHz 4GB DDR3 RAM 250GB HDD EL-CAPITAN 618996989331 | eBay
Apple iMac Mid 2011 A1311 21.5" Intel Core I7 2.8ghz 4gb RAM 1tb HDD OS X Sierra for sale online | eBay
iMac (Early 2009) | Low End Mac
Amazon.com: Bootable USB MacOS El Capitan High Sierra Mojave Catalina 4-in-1
SOLVED: Upgrade OS to High Sierra? - iMac Intel 20" EMC 2316 (Edu) - iFixit
iMac 24" 2.66GHz (Early 2009)* | mac of all trades
PSA: macOS Sierra drops support for many Macs from 2007, 2008, and 2009 | Ars Technica
Early-2009 iMac 24" for only $35! : r/mac
