[Grezzo]

My amp only takes optical for digital surround, my TV takes HDMI video. My HTPC has neither (I think it has 5.1 analog outputs).

Is there a card that will do both optical audio and HDMI video, or do I need two separate cards (or even a different motherboard)?

[eskro]

either your motherboard has onBoard Optical

or if not there's audio cards that do.
http://www.amazon.com/PPA-International-...826&sr=8-1

your GPU will have HDMI only.