Hello again. I have an 'old' machine, it shipped with Tiger. It's currently running Lion and I notice a significant performance degradation. I remember (and looking at old videos) that it would boot up much faster, open applications faster, etc. Some people talk about doing a clean install. I've never done that so I don't know if it will change anything or by how much. How much of a performance boost do you get? Another question is whether time machine "works" with a clean install. What's the point of doing a clean install if you put all the bits back into their place? Thank-you.