Best memory for 2020 iMac (27-inch): upgrade your RAM today | iMore
OWC 64GB (4 x 16GB) PC21300 DDR4 2666MHz SO-DIMMs Memory Compatible with Mac Mini 2018, iMac 2019 and up, and Compatible PCs (OWC2666DDR4S64S) at Amazon.com
OWC Announces RAM Upgrades for New 27-Inch 5K iMacs - MacRumors
256.0GB(4 x 64GB 2666MHZ DDR4 LRDIMM PC4-21300) OWC Memory Upgrade Kit for iMac Pro (2017 - Current) - ynzal.com
OWC Memory
Memory Upgrades for 2019-2020 iMac 27-Inch - Up to 128GB
64GB RAM upgrade kit for 21.5-inch iMAC now offered by OWC - 9to5Mac
OWC 64GB Matched Memory Upgrade Kit (2 x 32GB) 2400MHz PC4-19200 DDR4 SO-DIMM with Tools and Adhesive Strips | Megamac
OWC 64GB (2 x 32GB) PC21300 DDR4 2666MHz SO-DIMMs Memory Compatible with Mac Mini 2018, iMac 2019 and up, Dell, HP, Lenovo, ASUS and Compatible PCs (OWC2666DDR4S64P) at Amazon.com