Upgrade your iMac's RAM in less than 5 minutes - YouTube
iMac RAM upgrade: Here's an affordable way to improve multitasking - CNET
How to upgrade the memory of a 27-inch iMac with Retina 5K display (Late 2014 - Mid 2015) iMac15,1 - YouTube
Review: 27-inch iMac with Retina 5K Display – Six Colors
16GB Kit 2 x 8GB Memory for Apple iMac Retina 5K 27 inch (Late 2014) Core i5 / i7 DDR3L 1600MHz PC3L-12800 SODIMM RAM (PARTS-QUICK Brand) at Amazon.com
Install memory in an iMac - Apple Support
CMS 32GB (4X8GB) DDR3 12800 1600MHz Non ECC SODIMM Memory Ram Upgrade Compatible with Apple® iMac Retina 5K 27-Inch (Late 2014) Core I5/I7 - A6 at Amazon.com
Timetec 16GB KIT(4x4GB) Compatible for Apple DDR3L 1600MHz PC3L-12800 CL11 for iMac (Mid 2011, Late 2012, Late 2013, Late 2014 Retina 5K, Mid 2015 Retina 5K) SODIMM Memory Module MAC RAM Upgrade at Amazon.com
iMac (Retina 5K, 27-inch, Late 2014) - Technical Specifications
Adamanta 64GB (2x32GB) Memory Upgrade for 2020 Apple iMac 27" w/Retina 5K Display, 2019 Apple iMac 27" w/Retina 5K Display, 2018 Apple Mac Mini DDR4 2666Mhz PC4-21300 SODIMM 2Rx8 CL19 1.2v DRAM
iMac with Retina 5K Display 2014/2015 Memory Upgrades
Install memory in an iMac - Apple Support
27 inch iMac with Retina 5k Display 2019 3.7GHz i5 2TB Fusion Drive 64GB RAM | Refurbished | Techable