With all updates installed and only on desktop (xfce, stable, 4.15 kernel), my PC draws 30W more than under windows. And it all seem to come from the Vega card. It becomes very hot and finally crashes the computer. It is used as a secondary card. My main card with display is a 1080Ti. The Vega also has a display connected (the same display, because it is not recognised in programs if not connected).
That's a pretty big issue, because the fan doesn't go faster it stays at would the card be in power save mode although the overheating is clear (can't put my hands on it).
It would be great if a quick fix could prevent it from burning. It seems the kernel just freezes and let the CG overheat further.