This bug is still from beta and never got fixed, the problem is the Vendors avatars and their background that has unlimited Gpu usage, not even the most intense fights with screen full of demons and spells flying everywhere dont skyrocket my Gpu like the town vendors.
Just remove his avatar and fireplace from his background that apparently is rendered at 8k 240Hz for some reason and put a picture of him instead.
This has been on-going since the game launched last year.
It has gotten a bit better, believe it or not.
Either its not easy to fix or its not a priority. Either way, no idea how long it will remain.
You also have the world map. It takes this the complete other direction. If you need to cool down your card and system, tab and leave your map open for a bit. That uses the least amount of power and GPU time.
I dont know what has changed but it got fixed over night it seems, i can open vendors without Gpu going bananas but not all of them, some still skyrocket the Gpu…