Forgive the (possibly) dumb question, but what's wrong with using onboard spdif to get sound out of a PC..why is a separate soundcard better?
Your on-board audio probably doesn't support GSIF (for Giga) and maybe not ASIO. If it's WDM-only, it may have a long latency. Also, it may only support consumer S/PDIF, which is a problem if your destination requires the pro-version.
thanks jon...that certainly answers my question