Why Sonnet needs 170GB MemoryWhen I do simulation
The meshing of both solvers is fundamentally different, and Sonnet's mesh defaults to most accurate = most memory requirement.
In Sonnet, having a small cell size can cause inefficient mesh on diagonals/irregular shapes if you use staircase mesh. Switching to conformal mesh will give excellent results with much less memory on these diagonal lines. However, the solver will automatically switch back to staircase ar vias and discontiniuities.
In your model I see a lot of "green" vias along the egdes of polygons - what is that? This will result in inefficient staircase mesh, so I think this is your main issue. If you use that for manual thick metal modelling, that's wrong because you should use the thick metal model instead (=compatible with conformal mesh). If you all these edge vias for stacking multiple layers, there are better ways to place the vias. You should really contact Sonnet support, they can help you to define a better model with much reduced memory requirement.