Background hissing noise question

Setup = PC USB > Musical Fidelity V-DAC > Matrix M-Stage amp > HD650 & SR325is

When I'm not playing any music and just turn the volume of my amp all the way up, there's TONS of noise.  When I move my mouse, there's a change in pitch in the noise. 

Now, when I unplug the USB cable from the DAC, it stops, even with the volume maxed. 

Is this due to the V-DAC being a synchronous DAC, which would in turn cause their to be more noise coming from the computer interfering with my setup? (correct me if I'm wrong)  

If my above assumptions are correct, am I safe to say that is the biggest benefit to an asynchronous setup?

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Ultimately, I am looking to reduce unwanted noise and improve the sound in my setup.

I just ordered the Musical Fidelity V-Link from Amazon for $100.......for that price, why not?

Since the V-Link will be asynchronous, should the unwanted computer noise stop? 

Ultimately I will be running USB>V-Link / V-Link Optical Out>V-DAC / V-DAC RCA>Matrix M-Stage 

Since the V-Link is self-powered by the USB's 5v current it won't be pulling anything from the wall, which should eliminate ground [earth] loop, right?

Then, if I use Optical from the V-Link to the V-DAC, the setup should be galvanic(ly) isolated, whereby "no direct current flows between the sections" - Wiki .... right?

If everything I just said is correct then this should, at least in theory, remedy the issue? 

In summary:

V-Link doesn't connect to wall, therefore eliminating potential for ground loop between this component

V-Link converts USB signal to Optical, which is galvanic(ly) isolated, thereby "preventing unwanted current from flowing between [the] two units..." -Wiki

V-DAC receives clean(er) signal than before without having the V-Link.

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Tear this apart if need be, but this is just how the concept of the V-Link makes sense in my head, aside from the buffer management aspect of the V-Link.