I assume the TriVista handles jitter reasonably well. That leaves the question whether you are getting bit-perfect output from motherboard. Are you?
There are many external USB to S/PDIF converters, stock or mod, that can do a good job feeding your TriVista from PC.
There are many external USB to S/PDIF converters, stock or mod, that can do a good job feeding your TriVista from PC.