[PB PM]

Just finished rendering the same test video on the late 2012 Mac Mini and the 2018 Mac Mini and the difference was larger than I thought it would be. The test video was 3m and 55 seconds, 1080P 60FPS, recorded at 20mbit/s and the original file was 1.09GB. I corrected white balance, added saturation, made some audio adjustments, added some transitions and that was all.

The files were all edited in the current version of iMovie, both running Mac OS 10.14.2.

Late 2012 Mac Mini = 13m 17s
Late 2018 Mac Mini = 6m 7s

Some additional notes:
The 2018 Mac Mini only seemed to be using 5 of the six cores, none of which appeared to be fully loaded, while rendering the video, leading me to believe that iMovie is taking advantage of Intel Quick Sync technology, that puts a good deal of the load onto the IGP. This must be done to save power, or heat buildup, otherwise it's an odd choice. The app quickly sucked up all 16GB of RAM, as expected. The temperatures remained stable at around 50ºC on the CPU core, but not sure how accurate that is, since the monitoring software I use has not been updated since before the new Mini was release. The 2012 Mini was using both cores, and took full advantage of hyper-threading that the older dual core i5s had.

I did not test the video on my desktop PC, since I cannot use the same software, which would skew the results. No testing on the old iMac either, since a) I gave it to a family member, b) cannot run the same OS. based on previous experience it would have been in the same ballpark as the 2018 Mac Mini though, liking coming in around 7-8 minutes.