I'll be testing over the course of the week as I can. I'll try to report back as well.
Follow up: still had some stuttering, showing up after quite some time. And only with BIAB, wavelab and/or Cubase active. All three graphics intensive programs IMO.
It's again like some buffer is gradually filling up, maybe related to USB, or even Direct X as cause?
So i installed the full latest version of AMD drivers again, and i'm trying various settings, see picture, but so far it seems the same. The lot works OK for sometimes quite a while, suddenly stuttering starts, and then i switch off my USB UFX, and for a short while i can work again. Only a reboot results in a longer stutter-free period. Tips welcome.