I want to use the PCH file to speed up the build, so i store the PCH file in a separate folder and reuse it when build the project later. but I have some #import *.dll in my stdafx.h. so if something changed in the *.dll, the PCH file need be recreated. my question is whether I can use multiple PCH files in 1 project, so that i can put the import *.dll to another PCH and only recreate this one if something changed in *.dll. thanks in advance :)