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
OWC Announces RAM Upgrades for New 27-Inch 5K iMacs - MacRumors
27 inch iMac with Retina 5k Display 2019 3.7GHz i5 2TB SSD 64GB RAM | Refurbished | Techable
Install memory in an iMac - Apple Support
How to upgrade the 27-inch 5K iMac (2019) with a massive 128GB of RAM [Video] - 9to5Mac
Memory Upgrades for 2019-2020 iMac 27-Inch - Up to 128GB