Swarm and biprocessor

Hi guys, my workstation has 2 porcessors but only one is rendering.

By default, LocalJobsDefaultProcessorCount was set to 42 proc. With this setup, the proc 0 is rendering but not the proc 1.
If I set 84 proc on swarm the proc 1 render but not the proc 0…

Any idea of how to make them work both?

Thanks for your help