Upgrade late 2012 21.5" iMAC 13.1 to SSD
which method should do? have 1tb 5400rpm drive in it. 1. add ssd in slot designated them. 2. replace 1tb hd 2.5" ssd drive. 3. add external thunderbolt or usb ssd drive. i'd suggest option 3 glued imacs can devil work on. connect usb3 or tb drive externally, clone operating system etc internal, select boot drive in system preferences > startup disk , away go. slight difficulty operating system upgrades update interior drive first, , on reboot external. used internal backup drive. Forums Macs Desktops iMac iPhone Mac OS & System Software iPad Apple Watch Notebooks iTunes Apple ID iCloud Desktop Computers Apple Music Professional Applications iPod iWork Apple TV iLife Wireless