They can indeed. However, in this case the biggest factor is the none use of ithreads. In the tests we did here we did a like for like test, which showed a significant improvement when we simply recompiled without ithread support. If we were to add compiler flags I'm sure we could improve further, but as others have mentioned, adding further optimisations could have side effects.
in reply to Re: The magic of threads
in thread How to make your Perl 30% faster
Barbie | Birmingham Perl Mongers user group | http://birmingham.pm.org/