Yesterday has been one of the best nights of playback ever.
It is my conclusion that the LPSU must matter, although I can't really pinpoint it.
I could say that the slight flavour which is in Windows 10 (it is grey-ish) now is not there. It is more snappy - sort of towards Windows 8. Meanwhile the music(ians) kept playing.
Actually it was so that in all of the ~4 hours I never really noticed anything. Nothing jumped out. Nothing disturbed. I didn't want to shut off any album either, meaning that I played a few (in full) only. So my test repertoire wasn't that large this time.