I've configured my SSAS connection to use HTTP and everything works fine. The problem is that the connection is very slow when I'm using just Basic Authentication and passing the username and password as part of the ConnectionString. If I change MSMDPUMP.dll IIS app to use Anonymous Authentication, the connection works "as fast" as without HTTP. Again, the problem is that Anonymous Authentication is not acceptable for me and I really need Basic Authenticated security.
What's happening with the Basic Authentication and is there a way to make it faster? The solution is unusable at the moment.