[Boost-users] Thread creation overhead & efficiency

I am a new user of boost::thread. After implementing it I found that it slowed down execution of my code. I suspect that it may be due to the overhead of thread creation. I am creating/destroying thread_group ojects many times (tens of thousands) during code execution. Pardon my naïve question, but is this a problem for performance? I noticed some reference to a thread pool on this list. Is a thread pool the best alternative in this situation? Thanks for any guidance, James