What is the right way to compile a fortran 77 file using the amd64 bits technology? If I write f77 -m64 -march=opteron file.f and then run a.out, the time of execution is so slow as if it I had´nt called to 64bits option. what is happening? -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.centos.org/pipermail/centos/attachments/20090218/4be31da7/attachment-0004.html>