Coarsest Mesh on HFSS?

Hello,
Does anyone know how I can set the coarsest mesh?
My solution frequency is 8.4 GHz, but the whole structure is 500 mm by 500 mm by 500 mm that HFSS runs out of memory when I run the simulation.
I always used default meshing, but what should be the maximum length or maximum number of elements?

Thanks in advance.

Better than running at coarse mesh, you can use the symmetry boundaries to cut your structure to a half or even to one quarter. Next option would be to add more RAM.

Also make sure you are not using fast sweep. It takes more memory.
To change the mesh options just right click on the object > assign mesh operation. The rest should be self explanatory.

Thank you guys for help. Really appreciate it.
It is still not working on my computer though... Would CST MWS be better suited for this design?

If your structure is not meshed well, results you obtain may not be correct. One option could be to use distribute the solve between different machine if you have a HPC license.