I see, because now I have the machine upgraded to GPU mode NG06, I think the CPUonly version is only useful for back up running in virtual machine in another machine to free up the
main GPU PC for other development/testing purposes. Therefore the strength needs to be similar to GPU version. So far it looks as if the CPUonly version is weaker than GPU version on same
number of playouts.
Any way, I think CPU only version is lower priority because NG06 is mainly designed for GPU linux box. Currently the low end GPU is so cheap. GTX 1050 can be bought at $100 USD and works well for NG06 setup.