What Mac Do I Have? How to Identify Apple's Different iMac Models & Generations
How to Identify Your iMac | iGotOffer
Apple 27" iMac with Retina 5K Display (Mid 2017) Z0TR-MNED43-BH
Adamanta 16GB (2x8GB) Memory Upgrade Compatible for 2017 Apple iMac 27"/21.5" Retina 5K/4K or Non-Retina Display DDR4 2400MHz PC4-19200 SODIMM 1Rx8 CL17 1.2v Single Rank RAM DRAM at Amazon.com
Timetec 32GB KIT(2x16GB) Compatible for Apple 2017 iMac (27-inch w/Retina 5K, 21.5-inch w/Retina 4K / Non-Retina 4K) DDR4 2400MHz PC4-19200 SODIMM MAC RAM Upgrade for iMac 18,1 / iMac 18,2 / iMac
Differences Between Mid-2017 and Early 2019 iMac Models: EveryMac.com