It doesn't seem to be an obvious problem with output to disk, but I don't know. The C++ code I've tested perform well. I have also tested other fortran codes, and they also perform well on both machines. But theparticular code I'm working on now, performs much worse on B than in A. Any suggestion?
Very interesting question. Without the actual fortran code, it is really tough to tell what actually might be going on. Could you please post the code or put it on the web so others can download it and test it?
raju