So a while back I bought an Onkyo HT-r390 and a Creative Soundblaster Titanium, i've been running an optical to the receiver, and have the encoder to read it as Dolby digital live for a few months. I was just curious if that provided the best sound quality? Over running hdmi from the video card to the reciever or some other set up.
HDMI is digital, so in theory it is "flawless." However, it is not. There is very minor distortion in the signal, not enough to hear but it is still there. For most people (including most audio junkies) RCA is fine, but if you have the option of a good HDMI connection and have it read as Dolby Digital Plus, that would be best.