Agree the Memory and CPU and Disk are the core minimum requirements for those “time to make a cup of coffee” times…
an i7 workstation I have has 1 proc, 4 cores, 8 threaded. So in the above example you see most likely 8 threads cooking shaders at a frequency of say 2.2 - 3.4 Ghz. Whenever you adjust textures to the terrain a chunk of the terrain has to recompile the shaders and depending on your mesh density it could be hundreds of shaders. A Dual Xeon workstation I have has slower cores 2.2ghz but 8 of them threaded to 16 and it surprisingly chews through shader recompiling. This is especially important when you are making new height maps and constantly flipping the ground mesh to find what grayscale works best.
Then for each texture type, when you blanket import “black” images to flatten TheIsland back to blank - you are looking at around 14,000 shaders per image and I usually import a second one once the UI starts responding again which brings me up to 28,000 cooking. This increases as you add more textures that need to blend on the same segment of the mesh.
If you are CPU bound (100% cpu) then cores is what you need.
16Gb is pushing it, and in some cases Unreal will threaten to purge if you don’t free up resources - this makes it a pain for a fully functional art workstation where I have 1.6GB photoshop documents loaded, Visual Studio for the website work, many browser windows for the documentation and forums etc. My dual Xeon has 24Gb of ram and it has not run into any problems.
When you are finally done with the major revamps that take extended full map scan cooks, then GPU is your friend where you can enable every visual effect your high end consumers will be able to see, go into immersion mode (full screen) and place your foliage, cut and carve, and paint your heart out. High frequency CPU is best for the single Unrealengine process which will inturn give you a less laggy experience, if you notice that your “smooth” tool is pausing then your not quite there - you should experience as soon as you click the terrain is smoothing and you can drag the mouse around and nicely paint with the terrain editing tools as if it was clay. (For a time I was stuck single clicking because things were so overburdened.)
Turn off Windows Defender real-time monitoring.
Watch processes in windows task manager for anything that you don’t need that consumes memory, Adobe Cloud, Autodesk, GitHub, and anything else unrelated like Curse and stuff you are not using - free the CPU cycles to be dedicated to the engine.
Disk is important for constantly updating state to disk and retrieving textures that are not cached in memory, IE when a shader recompiles the textures this is done with CPU as a pre-game asset, once its a game asset its moved into GPU so you can see it in all its glory (specular maps, lighting, and all).
So the idea is, if you are waiting - and your CPU is not bound, check Disk - if Disk is not 100% utilized (queued) then it is finally most likely the GPU that cannot keep the world in memory and keep up with computations - this can be monitored from the show stats show fps option of the viewport.
Search for High Performance CPU Benchmark graph to see where your processor ranks, in this type of workload high frequency is desireable but more cores will ultimately save you lots of time. Solid state is really the only way to go as you save out 1.6Gb PDF’s or extract the latest updates to ARK Dev Kit, load it up, save it - all of that is directly bound by the disk and your mean time to load/update/publish will be slowly drained by a lack in disk availability