This is for those of you who are using a Windows computer for their source and are not afraid to do a little BIOS surgery. I am running Win 8 on an i7 (3770) based system with an Intel mobo. In playing with most everything that I could in the BIOS I discovered that dropping the CPU voltage made an incredible improvement in the sound. By dropping from four cores to one I was able to have a stable system running Vcc at 1.0V (down from 1.5V).
Please try this if you are familiar with BIOS adjustments and forget about what you think will sound better vis a vis the number of operating cores etc. Undervolting the CPU cannot harm your system! I do not know of anyone out there that has tried this for audio playback enhancement yet but maybe I’m not looking in the right corner of the Web. At my house this has been the single biggest jump in sound quality that I can remember. Bigger than going from PWD II to DS Dac. As always, YMMV, but if this is repeatable on different PC’s we may be on to something totally new. Another forum member has sent this info to Highend-Audio PC (the AO folks) to see if they get any traction from it. It may be totally unique to my CPU/mobo but I hope not. It never ceases to amaze me how the source, be it digital or analog, makes such a huge difference in the final product.
Good luck and Merry Christmas