iMac 2019 - upgraded w 2 extra ram and the speed dropped to 2400 MHz? | MacRumors Forums
Amazon.com: OWC 32GB PC19200 DDR4 2400MHz SO-DIMM Memory Compatible with 21.5" and 27" iMac Retina Models (Mid 2017), Mac Mini (Late 2018), and Compatible PCs (OWC2400DDR4S32G) : Everything Else
256GB (2x128GB) DDR4 ECC Memory Kit - Apple
NEMIX RAM Compatible for 128GB (4x32GB) DDR4 2666MHz PC4-21300 SODIMM Memory Upgrade for Apple iMac Mid 2020 (iMac 20,1/20,2) / Mid 2019 (iMac19,1) 27-inch w/Retina 5K, Late 2018 Mac Mini 8,1 at Amazon.com
OWC 32GB (2 x 16GB) PC19200 DDR4 2400MHz 260pin SO-DIMMs Memory Ram Upgrade Compatible with 27" and 21.5" iMac (Mid 2017), and Compatible PCs (OWC2400DDR4S32P) at Amazon.com
Amazon.com: A-Tech 8GB RAM for Apple iMac & Mac Mini (2018, 2019 & 2020) | DDR4 2666 MHz SODIMM PC4-21300 / PC4-21333 260-Pin SO-DIMM Memory Upgrade : Electronics
parts-quick 8GB (2 X 4GB) Kit Memory Module for Apple iMac 27" 2017 5K Retina Display DDR4 2400MHz SO-DIMM RAM at Amazon.com
Memory Upgrades for 2019-2020 iMac 27-Inch - Up to 128GB
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
Adamanta 64GB (2x32GB) Memory Upgrade for 2020 Apple iMac 27" w/Retina 5K Display, 2019 Apple
16GB Memory for Apple iMac Retina 5K, 27-inch (2020) DDR4 2666 MHz PC4-21300 RAM | eBay
64GB Memory Upgrade for 2019-2020 Apple iMac (27-inch)
Amazon.com: A-Tech 8GB RAM for Apple iMac & Mac Mini (2018, 2019 & 2020) | DDR4 2666 MHz SODIMM PC4-21300 / PC4-21333 260-Pin SO-DIMM Memory Upgrade : Electronics
Factory Original 32GB (2x16GB) Memory Upgrade for 2020 & 2019 Apple iMac 27" w/Retina 5K Display & 2018 Apple Mac Mini DDR4 2666Mhz PC4-21300 SODIMM 2Rx8 CL19 1.2v RAM Adamanta at Amazon.com
Crucial 32GB 2 x 16GB DDR4 SDRAM Memory Kit For iMac 32 GB 2 x 16GB DDR4 2666PC4 21300 DDR4 SDRAM 2666 MHz CL19 1.20 V Non ECC Unbuffered 260 pin SoDIMM - Office Depot
Amazon.com: A-Tech 32GB Kit (2x16GB) RAM for Apple iMac & Mac Mini (2018, 2019 & 2020) | DDR4 2666 MHz SODIMM PC4-21300 / PC4-21333 260-Pin SO-DIMM Memory Upgrade : Electronics
Factory Original 64GB (2x32GB) Memory Upgrade for 2020 & 2019 Apple iMac 27" w/Retina 5K Display & 2018 Apple Mac Mini DDR4 2666Mhz PC4-21300 SODIMM 2Rx8 CL19 1.2v RAM Adamanta at Amazon.com
Amazon.com: V-Color 32GB(2x16GB) 2666MHz ddr4 Compatible for iMac Retina 5K, 27-inch, 2019 and iMac Retina 5K, 27-inch, 2020 Non ecc SODIMM Mac Memory Ram Upgrade pc4-21300 CL19 260-pin 1.2V (TN416G26D819K-VC) : Everything
Apple Memory Module 16GB DDR4 2400MHz SO-DIMM (2x8GB) - Apple