Bad onboard audio and white noise, will a DAC/AMP help?

Excuse my ignorance but I haven't been able to find much on this topic, other than that a DAC/AMP might fix it so I'm looking for some input on this. My onboard audio is kinda wack because I opted for a budget motherboard to cut costs about 3 years back. I didn't really care at first but now the white noise and hissing annoys me and I was thinking a DAC/AMP like the Fiio e10k would fix my problems. The thing that confuses me is the soundcard part. As far as I understand I wouldn't need to get a soundcard if I just get the Fiio, but I'm not quite sure. So this begs the question, do I need to get a soundcard to go along with the Fiio (or maybe just buy a Creative Soundblaster)?

TL;DR: Onboard audio sucks and has white noise going on. Will a DAC/AMP like the Fiio e10k fix it or do I need a soundcard as well?