Just wondering.....does this Turtle Beach card use software rendering, or is it like the Sound Blaster series that uses hardware acceleration?
If it's software based, then the on board card will blow the Turtle Beach (T.B.) card OUT OF THE WATER. Just by sheer connection bandwidth, anything onboard from a decent manufacture like ASUS (the board I included in my quotes/suggestions) will win unless the T.B. card has it's own processor dedicated to sound rendering.
By the way, looking at the extreme lack of chips on the PCB, it's a Software-based accelerator. I won't state it as a fact, as I have never owned one, but I've never owned one for a reason.

I use Creative's Sound Blaster Series or nothing at all. 0 exceptions. I have for over 10 years, and I will in the future.
I do NOT, however, do any kind of audio editing. Are there any applications out there that can make a software-based card sing? Nothing can make a soft-base card out-perform a dedicated hardware accelerator, period, and that's a fact.
Comparing (I am assuming here^^see above^^) a software accelerated card to another software accelerated card is always easy. He who has the best bandwidth, wins. If you think a PCI/PCIe connected card trumps a direct-tie to the Northbridge, you need to do a bit more reasearch. If the on board sound is connected to the Southbridge, then you're starting to get into the 'nominal' difference range. Either way, a software-based addon card < on board, hands-down.
Not trying to bite anyone's head off, or point any fingers. I'm really looking for someone to prove me wrong and I'll change the ways I'm so set in!
*PLEASE don't post 'You're Wrong' without having some #'s and references, as this won't help anyone.*
A little more info:
http://www.extremetech.com/article2/0,2845,2064238,00.asp