Ethernet and USB cables

Absolutely I had both, my Bricasti is both a very good dac,and streamer the Ethernet  cable has a lower noise floor.
that being said ethernet,or usb the New Wireworld Platinum 8
is a outstanding cable that truly brings out added detail and musicality, highly recommended 1m minimum .

After much ’messing about’ with cables my conclusion was: for long runs optical is best followed by cat 8 down to cat 5. I did not try Hifi quality for this section as the run is 20 meters. For shorter runs I found small differences between cables. There are some very good Hifi quality less expensive cables around. 
For USB there are significant sonic differences, and shorter lengths definitely improves the sound. A friend of mine makes his own and a 20cm cable of his were amongst the best, competing with multi hundred $ cables. In his design he closes off the fifth pin in the usb, the one delivering 5v power - if your DAC does not require any power from the USB, and many don’t, he finds this helps reduce noise from the cable. If your DAC does use the fifth contact oin then this cable won’t work. 
You can actually do this with any usb cable - simply tape over the right hand pin on one end. It’s an easy test and you might hear a difference.

Kind of odd that the OP claims he has good cables between his other components but is asking if good cables matter to a server. Any good quality component can benefit from better cables, especially a source component 

Bits is bits as they say.
Put in any old cable.  Measure the error rate.
It will max at about 2 or 3 per million.
The other 999,998 will come through perfectly.
You can't hear the two that don't.

End of answer, apart from dither and clock error that are not products of cable, so far as I know.

p05129 what may seem odd to you is not to others. My claim to have some good cables is based out trying different ones but, I haven’t tried other USB or Ethernet cables. I was hoping to minimize that process and I thank everyone who has helped by sharing their experiences. This is a great forum because I’m getting feedback from so many audio fans.