I've been experimenting with some computer audio sources and came across a fairly significant discovery. I own a Mac Book Pro and for the longest time I was running all my Music off an external WD USB 500 GB Harddrive. Recently, I switched to a Firewire Lacie 1TB (two 500 GB drives that can be set to back the other up.)
Anyway, the discovery is that running a USB Dac with a firewire drive resulted in WAAAAYYY better sound! Everything sounded better, not even worth discussing nuances because it was drastic all around. I think my previous setup of a USB DAC with a USB HDD must have bottlenecked whatever resources are required by my computer to run the USB connections.