Timetec 64GB KIT (4x16GB) Compatible for Apple 2017 iMac (27-inch w/Retina 5K Display) DDR4 2400MHz PC4-19200 1Rx8 CL17 1.2V Non-ECC Non-Parity Unbuffered SODIMM Memory MAC RAM Upgrade for iMac 18,3 at Amazon.com
How to upgrade RAM in the (Mid 2017) 5K iMac and save up to ~$900 [Video] - 9to5Mac
Crucial DDR4 kit 16 GB 2 x 8 GB SO DIMM 260 pin 2400 MHz PC4 19200 CL17 1.2 V unbuffered non ECC for Apple iMac with Retina 5K display Mid 2017 - Office Depot
Crucial DDR4 kit 16 GB 2 x 8 GB SO DIMM 260 pin 2400 MHz PC4 19200 CL17 1.2 V unbuffered non ECC for Apple iMac with Retina 5K display Mid 2017 - Office Depot
Apple A Grade Desktop Computer 27-inch iMac A1419 2017 MNEA2LL/A 3.5 GHz Core i5 (I5-7600) 32GB RAM 2 TB SSD Storage Mac OS Include Keyboard and Mouse - Walmart.com
A-Tech 32GB (2x16GB) RAM for Apple iMac 2017 (27 inch Retina 5K & 21.5 inch Retina 4K) | DDR4 2400MHz SODIMM PC4-19200 2Rx8 1.2V 260-Pin SO-DIMM Memory Upgrade Kit at Amazon.com