| posts: 1,254 | Location: Iowa
Short answer is, yes, it would be worth using the xonar.
It really depends on what speakers you're using. If you're using the standard set of 2.0 speakers that came with some pre-boxed pc, don't bother. If you're using any "decent" pc speakers or going through a stereo etc... then yes, bother.
I'm not a fan of my onboard even though it's touted as above average. I did exactly what you're talking about on my last board, too. A pci xonar vs onboard and the xonar was IMO (these things are subjective) clearly superior.