Adamanta 16GB (1x16GB) 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
How to Install Memory Into a 27-Inch Apple iMac (Late 2015 - 2020) iMac17,1 iMac18,3 iMac19,1 - YouTube
NEMIX RAM 32GB Upgrade Kit (2x16GB) DDR4 2666MHz PC4-21300 SODIMM Memory Compatible for Apple iMac Mid 2020 iMac (20,1 / 20,2) / Mid 2019 iMac (19,1) 27-inch w/Retina 5K, Late 2018 Mac Mini (8,1) at Amazon.com
How to upgrade the 27-inch 5K iMac (2019) with a massive 128GB of RAM [Video] - 9to5Mac
iMac 27-Inch With 5K Retina Review 2018 - Rating Apple's New iMac With 5K Retina Display