Why does Visual Studio 2010 create ipch folder and .sdf file?

You’ll find a folder named ipch and a large file with file extension .sdf if you use Visual Studio 2010. They exist for precompiled header files and intellisense. You don’t like it, but you’d still like to use intellisense and precompiled header. Visual Studio 2010 let you change the location of these temporary files. Open you Visual Studio 2010, and left click “Tools > Options”, choose “Text Editor > C/C++ > Advanced”, scroll down until “Fallback Location” appears. Make “Always use Fallback Location” and “Do Not Warn if Fallback Location” to be “True”, and choose a “Fallback Location” you like. Just like the below.

Close Visual Studio 2010, and delete ipch and .sdf file, open VS. Now the folder and the file will be created at the location you specified.

http://wronso.com/blog/553/why-does-visual-studio-2010-create-ipch-folder-and-sdf-file.html