Question Is it better to run MacOS Mojave off an external SSD or off the included Fusion Drive?


Apr 4, 2017
I just got a new 5k iMac. For specific reasons (living in a third world country and restricted time as i was on vacations) I had to get the 27 inch 5k base model. I did a 32 gb ram upgrade and bought an external ssd. Im currently running Mojave off the ssd with no problems, everything is pretty snappy and fast. I've hadn't had a single issue yet. But im wondering:

The fusion drive is a 30 gb ssd (about 800MB/s read write) mixed with a 7200 rpm hdd. As I did not quite trust this Fusion Drive, I immediately installed mac os on the external ssd and im getting about 480 MB/s read write (samsung t5 500GB portable ssd).

What do you guys think about what im currently doing? The SSD part on the fusion drive is quite faster (on paper) than my external ssd. And the OS is of course installed there.

I do care about load times, and my heavy usage would be Final Cut Pro to edit video advertisements. I also pay close attention to the system snappiness. Do you guys think that running the OS on the fusion drive (in which the OS is installed on the fast ssd part) would be a noticeable difference than running it from the T5 external ssd? I have to say that im currently very happy with the system overall feel and speed.

Thanks in advance,