Hmm. I’m a little confused on that point…
I’d have assumed that that if the Nvidea card has S-video outputs, and an external Canopus or ADS box has S-video outputs, the same digital-to-analog transcoding is being done either way — and that the external box simply gets the DV signal via firewire rather than being attached to the motherboard.
Am I missing something special about the conversion that an external box (or my camcorder) performs that an onboard card doesn’t do?