This is a followup to a previous question.
I asked about setting rendering quality in the City Sample demo, and I got a very helpful answer from user @SupportiveEntity. However now I’m not sure what to do about scalability. When I tried the solution, I started having memory crashes. That still happens, and I’m not really sure what I can do about it.
Unfortunately, I don’t have any record of the message I’m getting. It didn’t occur to me to write it down. 
Hey there @MozayIC! I actually just came across your original thread in my backlog before I checked this notification and gave a bit of an update over there. Scalability being lowered should help keep you from running out of Vram, but it won’t help much for standard memory running out. How much ram do you have and how complex is your scene?
For my project I’m using the City Sample Demo Asset Pack - Small Map. At the largest filesize, I’ll need to have several of the large city skybox cities surrounding the island city. The open world is rendering NPCs on sidewalks and streets constantly. I also don’t think I can set the draw distance.
I have 32gb of ram.
So the best way to see what’s going on is (once you can launch the project that is) is to do some profiling and see what’s doing the most damage. Performance optimization is such a broad field. I’d usually have some tips based on the example asset in question, but I haven’t had a spare 100gbs laying around on my primary drives to look at the city sample. So without seeing everything done with the project thus far I’ll recommend the profiling tools to point out the biggest problems then work from that information.