Install the soundcard.
You can do a comparative test before you install it though.
But it will be pretty clear once you install it = much better.
I have 2 mobos with ALC889 both now have cards in them.
If you have the sound card already then you should use it as it will be better than the onboard chip that comes with the motherboard. There is no comparison the Clario is going to give better sound and more options.