iMac Late-2012 21.5" RAM Upgrade guide (iMac13,1) Rod Bland September 18, 2019 02:33 Updated Follow Use this guide to upgrade the RAM in your Late-2012 21.5" iMac to a maximum of 16GB (8GB x2). Tools iMac General Servicing Kit iMac Opening Tool Anti-static wrist strap Medium Anti-static mat Parts 4GB RAM Module 8GB RAM Module