How to Install Ram on the 2019 27 inch iMac and which Ram to Buy? - YouTube
Installation de mémoire dans un iMac - Assistance Apple (FR)
Install memory in an iMac - Apple Support
How to Upgrade/Replace the Memory in a 21.5-inch iMac (2019) on Vimeo
Timetec 32GB KIT(2x16GB) Compatible for Apple DDR4 2666MHz / 2667MHz for Mid 2020 iMac (20,1/20,2) / Mid 2019 iMac (19,1) 27-inch w/Retina 5K, Late 2018 Mac Mini (8,1) PC4-21333 /PC4-21300 MAC RAM at Amazon.com
How to upgrade the 27-inch 5K iMac (2019) with a massive 128GB of RAM [Video] - 9to5Mac