Hi I upgraded my project to use boost 1.74 instead of boost 1.49. After the upgrade serialization time for my project archive is extremely slow. With boost 1.49 my project archive was serialized about 1 to 2 minutes. With boost 1.74 it takes more than 50 minutes (I stopped the process so I do not know the exact time it takes) to do the serialization. I am experiencing this only when doing xml serialization. Binary serialization is good, maybe just one second difference between 1.49 and 1.74. What could be the problem with xml serialization ? Repeatedly stopping and playing the debugger gets me into this function in the call stack: save_start i.e in save(*) where it saves the name of the attribute in the xml archive. and then in save_iterator. basic_xml_oarchive<Archive>::save_start(const char *name) { if(NULL == name) return; // be sure name has no invalid characters std::for_each(name, name + std::strlen(name), detail::XML_name<const char>()); end_preamble(); if(depth > 0){ this->This()->put('\n'); indent(); } ++depth; this->This()->put('<'); this->This()->save(name); (*) pending_preamble = true; indent_next = false; } And then save(name) calls this function template<class InputIterator> void save_iterator(std::wostream &os, InputIterator begin, InputIterator end){ typedef iterators::wchar_from_mb< iterators::xml_escape<InputIterator> > xmbtows; std::copy( xmbtows(begin), xmbtows(end), boost::archive::iterators::ostream_iterator<wchar_t>(os) ); }