Don't Upgrade The RAM In Your New Apple iMac, Do This Instead
iMac RAM upgrade: Here's an affordable way to improve multitasking - CNET
iMac Retina 5K: Memory upgrade (RAM)
Amazon.com: OWC 32GB (2 x 16GB) PC19200 DDR4 2400MHz SO-DIMMs Memory Compatible with Mac Mini (Late 2018), 27" and 21.5" iMac (Mid 2017), and Compatible PCs (OWC2400DDR4S32P) : Everything Else
How To Upgrade RAM in a Mac | Macworld
How to upgrade the 27-inch 5K iMac (2019) with a massive 128GB of RAM [Video] - 9to5Mac
The New 2017 iMac: Notes & Tidbits on RAM - The Mac Observer