I suppose we must presume that the OS's under test were all used before installing software. Third party software, with its associated DLL's etc, slows down the performance considerably.
In my own case, as I said in a much earlier thread, I have a well tuned and customised Vista ultimate (64 bit). Applying the same customisation to 7 does not improve it, so far, to any benching figures I try privately. In several cases my Vista outperforms 7. I can see no way, with my existing hardware, I can get any close to Adrian Hughes' (unimportant) startup figures.
I think I have just about covered everything that is possible in 7. It is, after all, very similar to Vista. All the reg hacks and other customising tricks I applied to Vista, also work in 7. In fact, with a couple of very marked exceptions, there is little of new interest.
I am not disappointed. This is not yet a Beta and I have high hopes. But, my own point of view, right or wrong, is that most of the "new" features could easily have been incorporated into Vista. As an addicted customiser, I have to agree with many comments that I have seen, that 7 is looking, for the moment, like a ready customised Vista - in other words, what Vista should have been.
I have erased 7 as it is wasting space on my computer, but I will certainly be trying future releases with enthusiasm.