Huh odd, I guess it depends quite heavily on the system? Just to check I cleaned my build folder and am building now, ~700 files that take around 5 minutes to compile. I don't notice a thing, CPU (Ryzen 7 7700X ) is fully maxed out. I know that I do notice it on my laptop, but there reducing from 16 to 12 or even 14 is enough. Having to reduce to 4 is very different from what I experience. Currently on manjaro, the laptop has ubuntu.