That is because you are most likely using the inefficient creation style, probably like this: shared_ptr<myClass> myPtr(new myClass(arg1,arg2)); Which will also new a struct inside the shared_ptr that holds that pointer and bookkeeping information. If you have read the shared_ptr documentation, the efficient creation style is this: shared_ptr<myClass> myPtr = make_shared<myClass>(arg1,arg2); Which will new both your class and the bookkeeping information in the same place in memory, increasing both the speed of creation (only one new), and speed of accessing (better cache coherency). When creating your objects at the same time (literally) as the shared_ptr, that should fix most of those speed issues.

That's not the point, make_shared can be used only when the object is created,but what I said is as follows: class Session : public boost::enable_shared_from_this<Session> { public: static void HandleRead(boost::weak_ptr<Session> session, const boost::system::error_code& error, size_t bytes_transferred) { if (session.expired()) return; ... } void Read() { // this line is very slow, // because boost::bind(&Session::HandleRead,shared_from_this(), ...) // causes extra new/delete operations socket_.async_read_some(boost::asio::buffer(...), boost::bind(&Session::HandleRead, shared_from_this(), _1, _2)); ... } void Close() { socket_.close(); } private: boost::asio::ip::tcp::socket socket_; }; std::set session_set; boost::shared_ptr<Session> session = boost::make_shared<Session>(); session_set.insert(session); session->Read(); .... session->Close(); session_set->erase(session); // session is destroyed here, if I replace static void HandleRead(weak_prt ...) with void HandleRead(...) and boost::bind(&Session::HandleRead, shared_from_this()...), with boost::bind(&Session::HandleRead, this, ...); the question I asked emerges: void HandleRead(const boost::system::error_code& error, size_t bytes_transferred) { if (error) //should I erase shared_from_this() from session_set? this object may have been destroyed... } .... session->Close(); session_set->erase(session); // session is destroyed here. if I don't do this here, where should I do ? HandleRead may not be registered ever...