The hard drives in the new 2018 Mac mini are PCIe which means they are
USB-C Gen 2 can handle the speeds of most (but not all) SSD drives. So unless you want a very high-end solution, you’ll be fine using an external SSD over USB. An external SSD drive plugged in via USB-C will only be 1/5 the speed of the new internal PCIe drives, but it’s still fast. The external SSD drive on my new mac mini is faster than the internal non-PCIe SSD drive on my previous mac mini.
My first purchase was a Samsung S5. It’s fast, it’s USB-C Gen 2, and it’s cheap. But it caused a 30-second delay each time my mac booted up. Apparently, this is a common problem
The drive I ended up using was the Seagate Fast SSD. It’s fast and works well. I purchased the 500GB version. I’ve already filled it up so end hindsight I publish should have gone for the 1 TB version but I was trying to save
Now that you’ve connected your drive you need to choose which data to store on it. I used to recommend using your new SSD as the boot drive, but given that the internal SSD drive is now faster, you are better off booting off your internal drive and just putting some files on the external drive.
I kept OSX and my applications on my internal boot drive, as well as my users home folder. So my internal SSD drive looks like this:
I moved most the large folders from inside my Users folder onto my external SSD. I did not change my home folder to be the external SSD. I copied the files out of my home folder. I did al this when I was migrating the data
Here’s what I moved to my new external SSD Drive:
When you move your Music, Pictures and MainStage files you need to tell iTunes, Apple Photos and Mainstage the new location.
For iTunes, firstly copy all your music files across to the new SSD. (users/yourname/music/iTunes) Then go to Preferences, Advanced, and find ‘iTunes Media folder location’. Click ‘Change’ and select the new folder.
For Photos you need to copy the folder called ‘Photo’s Library’ across, then restart the Photos App while holding the Option key. This gives you the option to select your new Photo library from the external SSD.
Photos should open the newly copied library and you should be able to see your photos. If that is the case then go to preferences and select ‘use as System Photo Library’ to make this change permanent.
There are some applications that will still want to use files from within your home folder on your internal SSD. That’s okay. I allow them to do that.
I find it helpful in my own mind to know which files are where so I have my documents, my music and my photos on my external SSD and I have everything else on my internal one.
But you can arrange them how you like.