Msvc10 toolchain always spend the same time when compiling....

Before, I used Mingw. I have the impression that little changes, in example, a simple line feed on my code, does not affect to the compiling process. That is, in this example, the compile process was very fast. (It is as the classes doesn't changed does not be recompiled..? )
Now with msvc10 toolchain, I always spend the same time when compile. A little change (the same line feed), means a slow compile process (as every class where recompiled ?... )

I'm not an expert with compiler issues, so I have no idea what is happen.
Any idea, tip or trick ? Thanks