The library is particularly useful for large collections. In the days before the library was introduced, it was hardly possible to load much more than 75,000 files in one go.
The library helps to store tag data in a database from which it can be retrieved for processing purposes - when the corresponding files are loaded also and the modification date is the same for the data set in the library and that of the file.
Files that are loaded for the first time need the same amount of time to load as modified files.
Loading files from a NAS always is much slower than loading files from an internal HDD or even SSD - so it could be that this setup is in fact the bottleneck.
I have a setup with one copy of my collection on an internal HDD and the library on an internal SSD and it takes some 10 minutes to load the whole collection of more than 1.3 TB of files.
The same set of files, only this time on an external HDD, connected via USB3.0 and the library on the same drive take more than a couple of hours to load.
So if you collection can be handled without getting an MP3tag crash or an "out of memory" error, then you can ignore the library.
For other collections there is probably no way around it.
And then the rule applies that is valid for all databases: use the fastest hardware and as much RAM you can get.
There is a thread that deals with the library and access speeds:
Just to be sure on what we’re talking about: you don’t observe any difference in reading speed even after the first initial read (which always takes the time it would need regardless of the Library being enabled or not)?
I open MP3Tag and it automatically starts in one of the two folders.
Then the "Reading Directory" window appears and takes 20 seconds to read 700 mp3 files.
I change to the other folder and it takes about 18 seconds to read 500 mp3 files.
I change back to the original folder and it takes 20 seconds again to read the 700 files.
Thanks again for your help.
It is the Nas drive. I moved all the files to an internal ssd and obviously it was faster at about 7 seconds, but this time is was even faster at about 5 seconds when changing back to the same folder on the ssd.
I have since put them back on the Nas as this gives me the best access to the files and will have to put up the loss of speed until 10Gb ethernet becomes more affordable.