Actually, I've seend benchmarks to the contrary. As usual with benchmarks, there's no useful data to understand them -- specifically not performance counter dat

Actually, I've seend benchmarks to the contrary. As usual with benchmarks, there's no useful data to understand them -- specifically not performance counter data. I've yet to see a good analysis and haven't been able to do it myself. Many large-scale computations actually aren't CPU-bound, except insofar as they spin in MPI; some do plenty of filesystem i/o, but at least with something like PVFS2, that can be just in user-space on the compute node.