64GB (2x32GB) NEMIX RAM Memory for 2019 Apple iMac 27 inch Retina 5K (iMac19,1 A2115), 2018 Apple Mac Mini (Macmini8,1 A1993) System Specific Memory - Newegg.com
Apple A Grade Desktop Computer 27-inch iMac A2115 2019 MRR02LL/A 3.6 GHz Core i9 (I9-9900K) 64GB RAM 1TB HDD & 256 GB SSD Storage Mac OS Include Keyboard and Mouse - Walmart.com
OWC Confirms 64GB of RAM in Apple 27" iMac 2017
Timetec 64GB KIT(2x32GB) Compatible for Apple DDR4 2666MHz for Mid 2020 iMac (20,1 / 20,2) / Mid 2019 iMac (19,1) 27-inch w/Retina 5K Display, Late 2018 Mac Mini (8,1) PC4-21333 / PC4-21300 MAC RAM at Amazon.com
Apple iMac 27", 3.6GHz 10-Core i9, 64GB RAM, 2TB SSD, Pro 5300, 10GbE Z0ZW001G7