I'm not sure other than the reasons regarding optimizations possible with statically linked libs. I know that there is also some overhead involved in calling dll functions as opposed to the static counterpart, but this surely is a small cost. Other than that, I am not sure. I am very glad to hear that you are working on the static problem though. The latest checkout from thread_dev branch revealed the use of thread specific storage in thread.cpp, so it looks like the latest work there may be making it more difficult to make a static subset... Peter Michael Glassford <glassfordm@hotmail.com> wrote: I'm working on supporting static linking in Boost.Threads. Have you determined why the statically linked version runs so much faster? Mike --------------------------------- Do you Yahoo!? Friends. Fun. Try the all-new Yahoo! Messenger