S/PDIF coaxial and optical for my pc?

[V_Game]

I wanted to do surround sound via my pc to my av reciver. but i dont have HDMI on my pc i only have S/PDIF coaxial and optical, which one shall i go for that does better sorround sound?

is there a way of sending hd / sorround audio via DVI? as my GPU only has 2 DVI out puts.

thanks

[Drpepper]

DVI does not output audio.HD audio via Hdmi only.
S/PDIF coaxial and optical.no difference.

[V_Game]

chears mate