I'm going to assume that your computer has Firewire 800, which has twice the bandwidth of Firewire 400, and also does not use the same port. That's not to say that you can't use one with the other, as you can get cables that have one end 400 and the other 800. If you actually want to use firewire, you might as well buy 800, as Firewire 400 and USB 2.0 operate at roughly the same speed.