Ok guys, thanks for all the input. After a long delay I finally tested my Bifrost/Asgard combo with my new optical cable. Now I will put a short little review on the comparison and my thoughts, but let me explain a few things first..
My setup has been PC -> AudioQuest USB -> Bifrost -> Asgard
Ok so what I did was listen to about 3 different songs, let my ears rest for a second then plugged in the test setup..
Test setup: PC -> Optical Cable -> Bifrost -> Asgard
I used only one pair of headphones for both of these and the pair i chose to use were the Sennheiser HD 650's.
Now, its really hard for me to tell a difference between sound unless I can listen to something, then listen to something else playing the same song IMMEDIATELY after. (and in this case it is impossible for such a test, because I only have one Asgard, and one Bifrost.)
Let me assure everyone that I am the type of person that does not make things up, I don't pretend to hear differences when I do not hear any difference. I am completely real on my opinions and needless to say, sometimes I don't get along with other audio enthusiasts with their head in the clouds. I'm very down to earth and only believe things when I hear them or see them. I don't make things up and that is one of my pet peeves about this "hobby". False claims make me very mad, and I also sometimes hate the fact that everyone's hearing is different, because that just adds on another layer of challenge when reading and understanding someone's thought process when it comes to audio.
With that out of the way let me explain a few facts about the 2 different setups.
My usb setup has served me well, the Bifrost makes a great soundcard for my computer. The one major complaint I have with my usb setup is that at higher volumes (once you start surpassing 50% volume) their would be jitter and it would sound like interference.. it wouldn't be extremely loud or anything, and for the most part you could only tell if nothing was playing, but it was there, and knowing its there with no music, is unsettling, because it probably is in the background WITH music, its just hard to notice. Something that would really make it louder and with even more distortion is when I would move the mouse, or click the mouse. I have tried incorporating a powered hub and the problem is still there.
When i swapped to optical, as you could guess (being highly resistant to electric interference and distortion) the optical cable completely removed this issue.
Now those are the facts, the following are things that aren't necessarily something I would call fact, because I feel it could be my head playing games with me. Like I said, i am not comfortable completely, unless I have 2 exact setups and can switch between them to tell the difference immediately. Anyway here are things that are possible..
Now, switching to optical and turning on a song I had been playing through usb made me think ok, this sounds a little clear, like there was a little smoke on the songs with USB, and it was always in the back of my head that there could possible be electric interference going on, and even sometimes I would hear a crack or pop in a song, but I would always pass it off as just part of the song so I never really kept tabs on which songs those were so it was impossible for me to test that, but let me say that with optical - there was no popping or glitching in any song that I played. The next impression I got was that drums sounded better, this happened on 2 of the 3 songs I listened to. The drums just seemed to sound better with optical, especially the snare. Now this is probably all in my head, and I hate the fact that I do not know for sure, but that is why i put a disclaimer.
Either way the facts remain, if anyone has any suggestions on how to clear up interference via usb, I would love to hear it, because the thought of using my onboard soundcard in anyway is really annoying to me, I dont know why, but it is. In the meantime I'm still going to be using usb just because of that fact, but if i can't find a fix for the interference at higher volumes, I will permanently switch to optical.
To sum everything up, I honestly feel that if i just found a way to clear up any emi, or popping, in the usb.. then the sounds between the two cables would basically be the exact same. And thats my real opinion.
(Also don't let me fool you into thinking the emi from the usb is completely noticeable all the time or anything, its just something that happens sometimes and ALL the time at really really high volume. Otherwise usb is pretty great, all things considered.)
Thanks for reading, please comment!