If you were truly going to compare - my EPH-O2D puts my DX/D1 to shame - and I don't care about the "amping" qualities, just pure sound.
For you however - I would suggest a low cost sound card.
On-board is great, especially nowadays, but anything dedicated is better.
As others suggested, take a look at the xonar range DG, DX etc. You'll be cheap and cheerful with that

Speaking of which:
http://www.overclock.net/t/1313987/asus-xonar-dg-5-1-sound-card-with-built-in-headphone-amp-lnib
I would buy that with no hesitations, and have already shared it on facebook in case any of my mates were interested in a soundcard.
$20....disgustingly cheap.
Edited by Totally Dubbed - 10/13/12 at 4:21am