Reemplazo de RAM del iMac Intel 21.5" Retina 4K Display (2017) - Guía de reparación iFixit
How to Upgrade/Install Memory in a 21.5-inch iMac (Mid 2017) iMac18,1 iMac18,2 - YouTube
Memory Upgrades for iMac 21.5-Inch 2012 - Late 2013
Teardown of new 21.5-inch iMac surprisingly reveals user-upgradable RAM, modular CPU - 9to5Mac
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