How to get editor to spawn more ShaderCompilerWorker threads?

I have a 6 core 12 thread xeon processor, when opening up the editor or doing a launch on something where a lot (1000+) shaders need to be built, for some reason only 2 shader compiler worker threads get launched and it takes a long time with CPU at 15-20% to get the shaders all built.

I’m pretty sure a year or so ago I was routinely seeing a lot of shader compiler threads getting spawned and the machine running near 100%.

Has something changed?

I looked all over for a solution to this and mostly found threads a year or more old.

Tried changing BuildConfiguration.xml MaxProcessorCount to several values, no visible change.
Tried editing BaseEngine.ini and changing NumUnusedShaderCompilingThreads to 1 and to 6, still no change.

So I figure either something has changed or I’m editing the wrong file.

It seems like BaseEngine.ini exists in a number of places, so maybe I’m editing the wrong file? I have tried editing
C:\Users\gcorson\Documents\Unreal Projects\SunTemple\Saved\StagedBuilds\WindowsNoEditor\Engine\Config
C:\Program Files\Epic Games\UE_4.19\Engine\Config

Neither seem to have any effect on the number of threads spawned.

How can get more shader compiling threads launching to use all my cores?

Tried a test on my windows 7 machine (above machine was win10) and was surprised to see 4-5 shader compiler threads running.

So the win7 4 core 8 thread machine is launching more CompilerWorkerThreads, burning 90% cpu and getting the job done faster than the win10 machine which is 6 core 12 thread and higher clock but only launching 2 CompilerWorkerThreads and burning 25% cpu?

Also, fairly recently all the old engines were uninstalled on both these machines and then re-installed with 4.19.1

Maybe there is some residue from an old install? I could try uninstalling and cleaning out all the old unreal directories before re-installing if you think that would help.

Very confused now, hopefully someone can help me with this.