Lito Yap
Ansys Employee
How are you running the simulation on your cluster? Can you share the command or submission script you use?
The application will try to use the number of processes depending on your simulation job. If you set your resources too much it will try to reduce this to an appropriate number. Try requesting and running with only 48 cores for this specific simulation file - this might give you better performance for your simulation. Each simulation/project file will require different resource for optimum performance. Over splicing/subscribing your simulation with more p[processes can affect the performance/speed.
These might help.
https://forum.ansys.com/discussion/25423/ansys-insight-determine-the-optimum-resource-configuration-to-run-lumerical-fdtd-simulations
https://support.lumerical.com/hc/en-us/articles/4403780894355#toc_4