SoundCard Vs DAC Which is better?

Is it worth for example buying a Essence STX, SoundBlaster Zxr over a Fiio e11 e11 or E6? or vice versa? What benefits do DAC's respectively hold over soundcards, or would I be wasting my money all together?

I've tried to find answers through Google but I just can't find a straight forward answer to this predicament.

I currently using DT770 Pro 80hms atm.

Cheeers.

Sound cards and DACs are pretty much the same, some people will say that DACs are better simply because they have less interference but properly designed sound cards don't shouldn't normally have interference because they are designed around not having interference. So I say its a personal choice especially if you are considering a ZXR or STX because they are shielded which means that they will have no interference on the analog side due to the shielding being a Faraday cage. So your choice

So it seems to be an apples vs oranges argument... anyway thanks for the quick reply man!

I have similiar headphones ( DT 770 pro LE 32 ohms ) and I use both the analog output of an Asus Xonar D2X and the analog output of a Stoner Acoustics UD110 v2 mini DAC to feed my amp. 

The Asus is better with Rock and EDM e.t.c, but the UD110 v2 is far better with more ' delicate ' music.

So both ;)