You can fairly easily install the latest macOS on such older iMacs [1]. It works well and gives them a new life. If you do it, consider increasing the memory to

You can fairly easily install the latest macOS on such older iMacs [1]. It works well and gives them a new life. If you do it, consider increasing the memory to the max (8 GB?), and replace the HD with SSD. Still plenty of power to use for email, web browsing, DJ station (Spotify and/or Sonos), and even to run Xcode. [1] http://dosdude1.com/mojave/ http://dosdude1.com/mojave/