Executable size difference between VS C++ 2008 Express and Professional

We see a size difference here when building our application in VC 2008 Express vs. VC 2008 Professional (both SP1). The EXE built by VC 2008 Professional is about 10%+ smaller. We are using the exact same project files, so all the settings are the same and we're 开发者_JAVA技巧also building on the same OS with the same platform SDK, DLLs etc. installed. Is there a known difference in code generation or what could cause this?

Not all of the optimizations available in the Professional editions are in the Express editions.

The vague but official word from Microsoft:

Visual C++ 2008 Express Edition includes the same core optimizing compiler that will be included with all other Visual Studio 2008 editions. Some new expanded optimization features, including Profile Guided Optimizations, will be available only in the Standard and above editions of Visual Studio 2008.

The Express version has a number of optimisations disabled, so the code will tend to be both slower and more bloated.