iMac RAM Upgrade mixing different memory sticks: 27” iMac late 2013 - YouTube
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Apple iMac 14,1 - 21.5" 2013 - Core i5-4570R 2.70GHz 8GB RAM 1TB HDD - Very Good 885909673780 | eBay
Amazon.com: Apple iMac 27in Late 2013 A1419 3.5ghz 8gb RAM 1TB HDD El Capitan (Renewed) : Electronics
How to Upgrade Memory in a 27-inch iMac (Late 2012-2013) iMac13,2 and iMac14,2 - YouTube
Apple iMac 21.5" All-in-One Desktop Core i3-3225 3.3GHz 4GB RAM 500GB HDD Mac OS Mojave Early-2013 w/ Keyboard & Mouse ME699LL/A
A-Tech 32GB Kit (4x8GB) RAM for Apple iMac (Late 2012, Late 2013, Late 2014, Mid 2015) | DDR3 1600MHz PC3-12800 SODIMM 204-Pin Memory Upgrade at Amazon.com
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How to Upgrade/Install Memory in a 21.5-inch iMac (Late 2012– Mid 2014) iMac14,1 iMac14,3 - YouTube