iMac Intel 21.5" Retina 4K Display (2017) RAM and SATA Hard Drive Upgrade - iFixit Repair Guide
Third-Party RAM for 27-inch iMac Still Far More Affordable Than Apple's Checkout Upgrade Options - MacRumors
How To Upgrade the RAM on the New 27-Inch iMac (2020) & Save Money! $$ - YouTube
Can you upgrade the RAM in the 27-inch iMac? | iMore
How to upgrade the 27-inch 5K iMac (2019) with a massive 128GB of RAM [Video] - 9to5Mac
How To Upgrade RAM in a Mac | Macworld
Adamanta 64GB (2x32GB) 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