The answer from Jimbo is a bit overcomplicated.
I don't wish to go through the procedure of installing for the sake of this post, but I seem to remember in the 7 installation you are not given an option of fast or full??
Your answer is - no. It does a quick format and rearranges the file system. For any intrepid hacker, the data is still there, although maybe a little scrambled in places. On the other forum where you posted, the last answer was, in that respect, incorrect.
Again, cannot cast my memory back, but I certainly do not remember XP taking that long?