 <p>Usually, attaching a debugger would not slow down an application too much (compared to starting the application from the debugger, which will set the heap in debug mode).</p> <p>But by default, the debugger will trace events (exceptions and OutputDebugString), and in your case, there may be too much of them. After attaching with the debugger, you can disable all exception handling. (Menu Debug/Event Filters, or command sxi). You have to change the handling for all events (<code>sxi *</code> means unknown events, and does not apply to all events). You can also disable all tracing with <code>.outmask-0xFFFFFFFF</code>. Then enable only the stack overflow event with <code>sxe -c ".outmask /d" sov</code></p>