OWC 32GB ram (4 x 8GB) PC14900 DDR3 1866MHz SO-DIMMs Memory upgrade kit Compatible with 2015 (Late) iMac 27" w/ Retina 5K Models Model ID: iMac17,1 3.2GHz & 3.3GHz Core i5 & 4.0GHz Core i7 and Compatible PCs. Total capacity - 32gb (4 x 8gb ddr3 1866 sodimm) ; data rate - 1866mt/s ; form factor - so dimm ; 204-pin ; pc speed - 14900 ; fully compliant with jedec specifications ; non-registered ; non-ecc ; Low noise 8-layer PCB ; Operating: 32°F to 185°F (0°C to 85°C) ; Unleash the true speed and performance of your system and applications. Experience increased efficiency and productivity. Open more apps and files, all at the same time. OWC lifetime limited warranty including the owc lifetime advanced replacement program. Every owc memory module is tested at our in-house lab so you can upgrade with the confidence that your memory is built-to-last. Save BIG vs factory memory options. Plus, select among options not offered by the factory. OWC makes it easy to find the perfect upgrade to fit your needs. Built to meet or exceed the toughest industry specs to provide years of worry-free service.