Same issue with my Sapphire Nitro+ 6800XT. Never had this issue with my other GPU prior to upgrading to this unit this last week.
msi b450 tomahawk max
superflower 850w psu gold
I've tried different settings in games and AMD Radeon software, new DP cable (Vesa Certified 1.4), reseating GPU and power connectors to/from PSU.
I've recently read that there's a conflicting issue with the AMD Audio driver + any other audio drive you have installed. So as of this post, I'm currently disabling the AMD Audio driver to see if this resolves anything.