How to upgrade RAM in the (Mid 2017) 5K iMac and save up to ~$900 [Video] - 9to5Mac
Apple iMac with Retina 5K Display (2017) review | Digital Trends
Apple iMac Pro 27-inch (2017) 3.0GHz 10-Core Intel Xeon W-2150B 64GB RAM 2TB SSD AMD Radeon Pro Vega 64
Apple A Grade Desktop Computer 27-inch iMac A1419 2017 MNED2LL/A 4.2 GHz Core i7 (I7-7700K) 48GB RAM 1 TB SSD Storage Mac OS Include Keyboard and Mouse - Walmart.com
Memory Upgrades for 2017 iMac 27-Inch
Configure your own 27-inch Apple iMac (2017) at OWC