i would probably say its better not to. I have only ever done it once and I spent the next 6 or so hours trying to figure out why norton antivirus was throwing fits. In the end I removed and reinstalled it
I seem to remember it working fine, I would wait until you have a clear indication either way tho. The Perfectfisk offline defrag interface is loaded after the point the SATA drivers are loaded so it should know.
"Please note that Bootvis.exe is not a tool that will improve boot/resume performance for end users. Contrary to some published reports, Bootvis.exe cannot reduce or alter a system's boot or resume performance. The boot optimization routines invoked by Bootvis.exe are built into Windows XP. These routines run automatically at pre-determined times as part of the normal operation of the operating system.... The Bootvis.exe tool is no longer available from this site." -Microsoft WHDC
Who gives anyway!?! I use Bootvis to optimise the boot routine of windows. Although they say it won't improve performance for 'end users', I do, however, find that it actually does help re-align the system files.
I only use it once after installing windows and before installing any other software on top. There is a noticable difference between using bootvis and not using bootvis.