Use this guide to upgrade the RAM in your Late-2014/Early-2015 27" iMac to a maximum of 32GB (8GB x4).
iMac Late 2014/Early 2015 27" Memory Upgrade guide (iMac15,1)
Use this guide to upgrade the RAM in your Late-2014/Early-2015 27" iMac to a maximum of 32GB (8GB x4).