well i have seen when copying using Fireware port 1394 hardly any system resource is needed... what needed is only large amount of HDD Space... but when u try to work with that RAW video, then we gonna miss a good system
as the video u get from DV using fireware port is in RAW format and in a huge size...

i mean a full 60min would take 10 - 15 GB (at least with my cam in modatare settings)... now u need to convert that in to playble format either in DVD or in CD... that process needs a huge system resourse...