CPU usage problem with swarm


I have 2 machines working together to build my lights, but as I need to keep a bit of power aside for other softwares, I limited the number of cores to 30 on 36… BUT unreal lightmass keeps using about 90-95% of the said CPUs… Is it a normal behaviour or not? And is there a way I can lower the CPU usage?

E5-2697v4, 1080Ti and 64GB of RAM

No one has any idea?