Onboard vs. Soundcard re:coax
 

I'm going to start setting up a proper audio setup for my computer - 5.1 mostly for gaming but some music too. I plan to use a receiver fed with digital coax. Is there any difference over using onboard vs. a sound card? I'm not sure if a sound card would do any post processing adding anything to the signal.

None.

Once you use digital its up to the receiving end to decode the signal.

Heh, that almost seems too easy. So what's with all the formats I hear about WRT sound cards and gaming (not familiar with them just know they exist... maybe ancient history too). I'm not going to miss out on any crazy sound effects?

Well, if you use a dedicated sound-card, you'll get better frames in games, especially if you like having the sound-quality on high. Also, X-Fi cards can still process X-Fi effects before sending the signal through digital, so if you like using X-Fi on supported games, that's something to consider.