Undertand where your coming from with the comment to shut down 'other' software that may conflict with each of the process's DVD Fab runs through but....... think this will depend on many factors, such as your rig/machine, user experience and knowledge and what other programs your trying to run.
Persoanally and I'm not saying this is right or wrong -- I normally do other stuff whilst backing up copies of DVD's with Fab -- e.g. surf net, word docs, update's and pacthes etc... and leave all my security apps in place and running.
I obvously avoid things that may cause conflicts/problems like disk defrags or processor intensive work, e.g. video editting and have never really had any issues.
My PC running XP, and is resonably fast and I'd class myself as resonable to good on the user/techncial side.
Average time for me to make a backup is around the 20-30mins mark, again depending on disk and options I choose and the only reason I do other things is that it's more productive than to just wait. All in all I only buy a few discs a week so don't have a huge time dependency and even then have a backlog of those that I want to copy so time is always the issue