I don't know. I do know, playing digital off the computer, either files or streams, works excellent with the on board sound chip(Azalea Audio) on my S30 or D30 Lenovo's, or the Modi DAC. The Modi 3 has a deeper black background on quiet passages.
The Asus Xonar Essence STX PCI Express Audio Card (marketed as a audiophile card) has a very different sound, more akin to a analog source, very pleasing, and very interesting software with Dolby.
The Asus U7 Mk ii USB sound card is very sterile sounding. And while it measures great for Room Equalizer Wizard use, it's primarily a gaming sound card, as the software demonstrates.
Personally, I wouldn't spend much $ on a DAC. The Modi 3 is as high as I'm willing to go.
And the Lenovo desktop (Home Theater PC if we want to get fancy) handles all streaming effortlessly and cheaply. I have a Lenovo D30 in the main system and a S30 upstairs in the "electronics room".