Importance of computer for DAC shootout


I am using a perfectwave DAC + bridge + modwright 36.5 LS/PS preamp to stream flacs over my network. Very happy with the sound, but intrigued by the idea of getting better SQ for less $$$ I will soon be auditioning an Antelope Zodiac Gold + Volticus over USB, directly into my poweramp. Being able to take out the modwright alone would pay for the new DAC. My only concern is the Computer I will be using for this shootout. I have a Dell laptop and an Asus media PC, both with USB 1.0.

If I opt for the Zodiac I will go all out on computer source (may be mach2music), but I don't want to invest before knowing if I even want to go down the USB path.

In you estimation, is there any chance of the computer used in my shootout distorting the outcome? Would I be better off using my Marantz ud9004 S/PDIF source for the Zodiac, and then get a better computer if the Zodiac wins the contest?

Or are the difference between computer sources small and will I be able to conclude which is the better DAC using a mediocre PC as the source for the Zodiac. Any advise on how to set up the hardware for the shootout is welcome.
edorr
For starters you might want to test file types and player programs. On my system I notice a distinct and repeatable difference in them (alac,flac,aiff and wav). Yes, I realize that there should be none, alas.

If your system can resolve those differences, there is a good chance that you will realize the benefits of other cpu related changes- just as with a turntable.

I am sure that someone will chime in here stating that I am a fool, and bits are bits. FWIW, I was very skeptical before I did the test. In fact, I needed to do the test three times over months before I would believe (in) it.
IMO performing the comparison with a computer that pre-dates USB 2.0 (and even USB 1.1, if your statement is correct) will tell you little or nothing about how the DAC's will behave with a modern computer. I would also be hesitant to extrapolate from results with your Marantz player.

You may find my post here to be of interest. Although it deals with transports rather than computers, depending on the particular DAC design similar considerations may be applicable.

Regards,
-- Al