Question Editor slows extreme down and GPU drives to 100%

I use a fresh install of unity 2019.4.10f1 (Latest LTS)
Then i have with different projects the problem that the editor slows down over time, and with GAIA-PRO for example a 4K Terrain with, or without terrain streaming slows the editor down to freeze.
GPU is at 100% CPU between 4% and 35% I have tested on very-low settings, also without light enabled.
I have installed newest driver on win64-pro and and my GTX 970
RAM is 32GB and i use 4 SSD-s (500mb/s r/w) to distribute cache and editor.
I also get through the forums and turn V-Snych on,off, blank..... no changes.

CPU is i5-4690k

In the past it was not a problem to create huge terrains with veggie up to 4k in minutes with same very-low settings.
Profiler give me no hints where the problem is.
I also disabled my AV program when working with unity, but no success.
I have no more ideas.