How to upgrade iMac (2020) RAM and save up to $2000 - 9to5Mac
2019 5K iMac RAM Upgrade Guide - YouTube
Install memory in an iMac - Apple Support
A-Tech 32GB Kit (4x8GB) RAM for Apple iMac (Late 2012, Late 2013, Late 2014, Mid 2015) | DDR3 1600MHz SODIMM PC3-12800 204-Pin SO-DIMM Max Memory Upgrade at Amazon.com