I use a Digiface with an HDSP PCI card with my desktop computer. The Digiface is powered by the PCI card over the firewire cable.

I've also got an external power supply that came with one of the old mobile Cardbus cards that I "bricked" when trying to update the firmware. My question is this: would there be any advantages to using the external power supply with the Digiface instead of powering it over the Firewire cable?
For example: decreased load on my computer's power supply, less strain/longer life for the PCI card, etc?

I read a forum post elsewhere in which someone stated that there was audible noise on the analog outputs of their Multiface when powering over Firewire, but using an external power supply reduced of eliminated the noise. Of course, I realize that's not a consideration since the Digiface doesn't have any analog outputs, but I just wondered if there would be any other benefits.

Also, powering it with the external supply in conjunction with the PCI card (which also supplies power) won't damage anything, will it?