How to Add An SSD To The 27" iMac (Late 2015) - iFixit Repair Guide
hard drive - iMac 27" late 2012 SSD upgrade - Ask Different
2011 imac 27" 32GB - final stage of 1TB + 2TB SSD upgrade (replaced HDD & optic drive). Also cleaned out the fans and case. Running 'SSD Fan Control' & 'Macs Fan
iMac 27 2012-2015 Hard Drive Replacement with SSD
iMac Repair & Upgrade, Same Day Services
How-To: Now's the right time to swap your old iMac's hard drive for a fast new SSD - 9to5Mac