OS X Mountain Lion comes in the form of a 4 GB installation package which, as you already notice from Table above, it installs in 13 or 57 minutes, depending on the Mac you own. Macs with built-in SSDs are the fastest and I can tell you that my Mac Mini solved the problem as quickly as a MacBook Air, but of course I installed an SSD in it. If you have a Mac with the classic Apple HDDs with 5400 RPM, then you will have to wait quite a while for the installation, but you can always buy an SSD.
