I am looking to buy a set of DT 990, 600 ohm. My computer is a desktop gaming style with the latest Asus ROG Maximus XI Extreme motherboard. The question is this: Can that motherboard drive them correctly or will it require an external amp/dac ? Im sure that an external amp/dac will be better for the sound, but I do not want to buy one right now. Finaly, is there a big difference of sound quality between the SoundblasterX g6, and lets say, a Fiio e10k or anything that is great for the DT 990, 600 ohm ?