 <p>STL containers in VS Debug are notoriously slow. Game programmers forums are rife with complaints about this. Often people choose alternative implementations. However, from what I've read, you can get a performance boost up front by disabling iterator debugging/checking:</p> <pre><code>#define _HAS_ITERATOR_DEBUGGING 0 #define _SECURE_SCL 0 </code></pre> <p>Other things that can affect debug performance are excessive calls to new and delete. Memory pools can help with that. You haven't provided details for <code>PropMsg::add_v_var_repeated()</code> or <code>PropMsg::~PropMsg()</code>, so I can't comment. But I assume there's a vector or other STL container inside that class?</p>