Memory Upgrades for iMac 27-Inch (2012 - Mid 2015)
Apple iMac 27 inch late 2013, 32GB RAM, 500GB SSD | eBay
Mac Pro (Late 2013) - 2.7GHZ 12-Core Xeon E5-2697v2 - SSD 1TB - RAM 32GB | Back Market
NEMIX RAM 32GB Kit (4x8GB Upgrade) DDR3-1600 SODIMM PC3-12800 for Apple MacBook Pro Mid 2012 / iMac Late 2012 / iMac 2013, Late 2014, Mid 2015, Mac Mini Late 2012 at Amazon.com
iMac RAM upgrade: Here's an affordable way to improve multitasking - CNET
iMac 27-Inch "Core i7" 3.5 Late 2013 Max RAM is higher than 32gb | MacRumors Forums
27in iMac Late 2013 - 32GB RAM - 500GB SSD - i5 for Sale in Glendale, CA - OfferUp
Timetec 32GB KIT(4x8GB) Compatible for Apple DDR3L 1600MHz PC3L-12800 CL11 for iMac (Mid 2011, Late 2012, Late 2013, Late 2014 Retina 5K, Mid 2015 Retina 5K) SODIMM Memory Module MAC RAM Upgrade at Amazon.com
Apple iMac (27-Inch, Late 2013) - Core i7-4771 3.5 GHz, 32GB RAM, 3TB Fusion, 775M - WBAM
Apple iMac 27-inch 3.2GHz Quad Core i5 32GB RAM 1TB HD NVIDIA 755M 1GB ,2013 | eBay
iMac | 3.2 GHz Core i5 | 27 Inch | Late 2013 - Techable.com
Configure your own 27-inch Apple iMac (2013) at OWC