I have a question for you. If you open the project and set everything up to work with DX12, how many FPS do you have in the viewport? Ray Trace must be on, of course. I have about 7-9 FPS here. How about yours?
My computer is 2 years old has 32 GB of memory and a Nvidia GTX 1080 with 8GB RAM.
Here you will get the Project-Files: New Archviz Interior Rendering sample project now available! - Unreal Engine.
Just go to your Epic Games Launcher and it should be there available under the Tab Unreal Engine.
Thanks a lot for your answers