Originally Posted by LexInVA
The 220 does not have PCI-E audio pass-through. I don't know why you think it does.
I don't know why you suggest connecting GT 220 to an audio card via the *included* SPDIF audio cable when there is no GT 220 card with S/PDIF in. (Perhaps you haven't used a GT 220 card.)
I am not sure what you mean by "pass-through". If you are thinking of a "cable" connecting a PCI Express slot and the graphics card by analogy with S/PDIF pass-through, there is no such thing in G210/GT 220/GT 240 or every GeForce card released later than that (or every Radeon HD 2000/3000/4000/5000/6000 series card). All of these cards have an audio controller in the graphics chip and grab audio streams from the system memory via PCI Express "bus" (I assume you know how to connect a graphics card to the PCI Express bus [through 32 pins in a PCI Express x16 slot]
). I recommend you to read one of the Radeon HD 2900 XT reviews (the first discrete graphics card with built-in HD audio controller), for example, PC Perspective
System memory -> HD audio controller in the chipset -> HD audio codec (well, just a S/PDIF emitter) -> GPU -> muxed with video stream in TMDS -> HDMI
Built-in audio controller
System memory -> PCI Express controller -> HD audio controller in GPU -> muxed with video stream in TMDS -> HDMI