Review on 💻 Gigastone 256GB 2.5" Internal SSD 2-Pack: Powerful SATA III 6Gb/s 2.5 inch 7mm Solid State Drives, Read up to 550MB/s by Sean Sitton

This drive was purchased for a mid 2011 21.5" iMac. I first placed the SSD in an external FW800/USB 2.0 enclosure and used Apple Disk Utility with the FW800 to mount the GUID (Mac Journaled) and in some cases the SSD was ready for a clean install of High Sierra 10.13.6 The macOS installation took about 20 minutes from the FW800 Boots well as a bootdisk from both Firewire 800 and as well as USB 2.0 connections Then did all the updates to High Sierra with no problems Install the SSD in the optical drive bay using a "data doubler" and start using the internal 500GB HDD for storage.