Re: Speedup in multi-calculation-nodes
are you using OpenMP or MPI for your simulations?
In general our current OpenMP code is not really efficient and it is generally recommended to use MPI for the current releases (we are working on an improved hybrid OpenMP + MPI mode).
In general we scale quite well (at least for weak scaling) but obviously as soon as you move from one node to two nodes you will get an overhead through the communication that now can no longer be implemented through shared memory copy operations.
However I think in general the performance for most cases should be somewhat stable. I will try to post some numbers from our own HPC system soon.