VS2008 binary 3x times slower than VS2005?

7
votes

I've just upgraded a native C++ project from VS2005-SP1 to VS2008-SP1
The first thing I tested was a very basic functionality test of the application and the first thing I noticed is that the main number-crunching algorithm performs three times slower in the VS2008 binary.
I tested again the VS2005 binary to make sure there isn't any other difference and it still performed as it did before.
Did anyone stumble into this?

1
c++visual-studio-2008performanceoptimizationvisual-studio-2005
Are you running optimized or debug? - David Norman
running release ofcourse - shoosh
Did you accidentally compile with different options? For example, did you compile for 64-bit Windows rather than 32-bit Windows? - Kevin

1 Answers

17
votes

Strangest. Thing. Ever.

It seems that the project upgrade wizard of vs2008 simply doesn't copy the 'Optimization="2"' property so the new project is left with no optimization in release.

The fix was to go to the properties dialog, change optimization to 1 and then back to 2. compile again and everything works it should.

I couldn't find any official reference for this only this obscure reference in an MSDN forum.