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
I need to check my configuration. If it turns out my Dell Laptop or Asus has USB 2.0 should I be OK?
All PCs are notoriously noisy platforms that interfere with the sound that comes out of them. They are great for ripping, storing, etc. but they are not the last word for playback. Make sure you have a really good media player that can isolate and run the playback while shutting off other programs that compete with the sound (I believe its called 'hog mode'--I'm still very new at this).

Without a good media player, all will be for naught.
10-12-11: Edorr
I need to check my configuration. If it turns out my Dell Laptop or Asus has USB 2.0 should I be OK?
That would be a lot better, but I think that using a computer that is several years old or more would still make the meaningfulness of the comparison very questionable.

In fact, based on the kinds of unpredictable interactions that can occur between a DAC and a digital source, such as those I cited in the post I linked to above, arguably it would be a good idea to perform the comparison with TWO modern computers (if neither is the one you would end up using).

Perhaps a reasonable compromise, though, would be to compare using the more recent of the two computers AND using the Marantz player, and seeing if you get consistent results.

Best regards,
-- Al
4est,
What is your preference in file types? What were the differences you heard?