> The obvious ones are fluid dynamics, weather simulations, n-body problems, and simulation of quantum systems. Those are typically run on distributed memory;

> The obvious ones are fluid dynamics, weather simulations, n-body problems, and simulation of quantum systems. Those are typically run on distributed memory; the question should probably have been about shared memory. They're likely to be memory bound, depending on the application, but it's not obvious that shared memory in ~100 cores would win. Then consider checkpointing, for instance. (In my experience it's bioscientists who think they need huge shared memory but may well not, or couldn't feed it fast enough anyhow.) Recent top supercomputers have had ~1PB or more total memory, though that's pretty variable, and there probably won't be many jobs using a large fraction of the machine. They may also (or only) have HBM.