You should keep your "working project folders" on the C drive with cake.
Move them to a storage drive when they are finished and accessing them is not as critical.
Loading Sonar to start with should only take a few seconds and same deal with projects. I don't pay too much attention to the actual load times of either the program or the projects.
My main concern is that they do load and that the system is stable. Whether it's 10 seconds or 30, it's still faster than tape for loading a project and getting ready to work. I'm generally doing something else during the loading anyway... grabbing project lyrics or setting up the guitar, so the actual time to load is inconsequential.