ram memory upgrade DDR4 2666Mhz for 21.5-inch 2019 iMac
NEMIX RAM 64GB Memory Upgrade Kit (2x32GB) SODIMM DDR4 2666MHz PC4-21300 Compatible for Apple iMac Mid 2020 (iMac20,1 / 20,2) / Mid 2019 (iMac19,1) 27-inch w/Retina 5K Display, Late 2018 Mac Mini 8,1 at Amazon.com
Adamanta 32GB (2x16GB) 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
DDR4 2666MHZ PC4-21300 SODIMM for Apple iMac Mid 2020 & Mid 2019 (iMac
iMac 2019 - upgraded w 2 extra ram and the speed dropped to 2400 MHz? | MacRumors Forums