Have you tried restarting the macMini running the Core?
Take into account a lot of analysis are done after the upgrade.
Relevant paragraphs in the changelog post:
After updating to 1.3, Roon will re-extract file tags from your library and then re-queue your files for audio analysis. This can place some extra load on your core until that work is complete, so consider this when deciding when to accept the update.
Starting in Roon 1.3, we have fully adopted the R128 volume leveling standards. Your music library will be re-analyzed automatically to extract R128 data, and the volume leveling features throughout the app will make use of it.
Finally, Roon’s Audio Analysis can now be configured to use all of your CPU cores, and several stability issues related to analysis have been addressed.
restarted the Mac mini and, maybe, found the issue
in “Library”, to speed up analysis, I had set to “8 core” analysis speed. looks this was slowing down rescan as, after setting it back to “Throttled”, rescan is now proceeding much faster
though… looks AIFF tracks (my collection is organized in subfolders by file format) take a veeery long time to be rescanned/re-imported (still 400+ albums missing)
I fully understand the issue is the rescan, but as there are so many scans/analysis happening after Roon is upgraded, one analysis can cause another scan to slow down.
Only very powerful system (Core i7 / Xeon E3/E5) were able to finish all these scans/analysis in a few hours on large libraries.
Let me know if the current remedy fully solves your issue to you expectation.
Or put it to 4 or 6 cores, to prevent a rescan slow-down in the future.
That last core is most of the time not giving you that much extra performance (due to overhead/scheduling of the tasks for a cpu), plus you can keep on playing music without issues directly after adding new albums