My C++ executable runs way faster outside the Visual Studio 2008 IDE than inside, even in release

Question

I build a C++ application that does some number crunching. I'm running in Visual Studio 2008 PRO SP1, in release mode, Windows 7 64 bit. If I run it inside the IDE, the application takes 4 minutes, if I run the same executable from windows explorer it takes 6 seconds! I have no clue. I have checked that this does not depend on the processor and operating system. I don't think I have strange VS plugins that are doing something in the background.

Any hints? Thank you in advance!

Marco

Answer 1

Presumably, the slow down is caused by the debugger being attached when you are starting the application in Visual Studio. This is the case even when you've built the program in "Release" mode.

To confirm that this is indeed the source of your problem, try running your application without the debugger, using the "Start Without Debugging" command or Ctrl+F5.

   

It's worth nothing that in C++ specifically, when you start without debugging, your program won't use the Windows debug heap. With the debugger attached, it will.