You might consider getting a Creative Sound Blaster Z (SB1500) sound card, $100.
Has a built in headphone amplifier and a CS4398 DAC chip :)
Plug your HD 380 Pro into it and see how you like the sound quality.
Or get a Schiit Magni headphone amplifier, $99, and plug it into the line-out/headphone jack on the motherboard, plug the HD 380 Pro into the Magni.
I would assume the Magni is a better headphone amplifier then the one built into the Z card.