I've been finding lately that sometimes when I play games that the HBM2 clocks will be stuck at 350Mhz with the occasional jump up to 800Mhz. This results in significantly reduced performance (20%+). I've found this only seems to happen after I've had Firefox or Discord open for a while (say 20-30 minutes) but I haven't worked out which one it is linked to. Accompanying this behaviour I have noticed that the UVD clocks in GPU-Z seem to be locked at some value above the 33Mhz idle so essentially the card thinks it is at load when it isn't. Only workaround I have found to this issue is a system restart (No I didn't leave my browser windows open). I've attached GPU-Z screens which show the normal and strange behaviour I am seeing.
Update: So it would seem that using Google Chrome fixes the issue. Still not sure if this is a driver bug or Firefox being dumb but this seems to be a workaround for now.
Ryzen Threadripper 2950X
MSI X399 Gaming Pro Carbon AC
4x8GB G.Skill Trident Z 3333Mhz
Samsung 950 Pro 500GB
Samsung 970 Evo 500GB
Samsung 840 Evo 500GB
WD Black 2TB
HGST Deskstar 6TB
WD Red 10TB
With the latest build of Windows, checked today.