The Pink Faun card doesn’t get power from the motherboard PCI connector. It has it’s own Molex power connector to feed it’s own power supply. Use a high quality power supply from someone like Seasonic and you should be all set. It shouldn’t have the noise issues you’re talking about due to how it’s designed. USB, in general, should really be avoided. I think a high quality optical solution, which can be quite expensive as typically glass optical cables are needed, or I2S should be used for optimal results. Here’s a blurb from their website (translated from Dutch as they’re based in The Netherlands):
High quality glass optical cables needn't be expensive at all, in fact in my system a $9 glass AT&T from Fry's sounds better than a top of the line glass cables from AudioQuest. The expense of high quality optical setups is in the transmitters, receivers and their associated electronics.
I’m not trying to be argumentative, but I don’t react well to overgeneralize statements: Electrical noise from a PC can’t be entirely avoided if there’s an electrical connection - taking steps such as separate power supplies, good filtering and good drivers can definitely help, but that doesn’t force you to use I2S over other solutions. Note I’m not putting down the Pink Faun product, I’m just pointing out that there’s nothing inherently superior about I2S over all other possible connections between a PC and a DAC. Other things in one’s system probably have more of an effect than the specific electrical connection between a PC and a DAC.
I also chastise Paul at times about overgeneralizing his specific experience to all other systems. Just like at shows, if you hear something good, it means that that sound is possible. If you hear something bad it doesn’t mean that everything (or anything) in that system is inherently bad. There are multiple ways of getting great sound and a lot of them depend on other components of your system.