How To Upgrade the RAM on the New 27-Inch iMac (2020) & Save Money! $$ - YouTube
Can I mixed ram size on 2019 iMac | MacRumors Forums
How to upgrade the RAM on the 27-Inch iMac (2020) | AppleInsider
OWC 16GB (2x8GB) ram Upgrade PC3-12800 DDR3L 1600MHz sodimm 204 Pin CL11 Memory Upgrade Kit Compatible with Late iMac, Mac Mini, and MacBook Pro Computer at Amazon.com
iMac RAM upgrade: Here's an affordable way to improve multitasking - CNET
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