Ethernet and USB cables


Do premium Ethernet and USB make a sonic difference? I have very good speaker and DAC to amp cables but, all the others are just inexpensive generic cables. I’m running Innuos Zenith MK III and about to try out a Phoenix USB. Just looking to get the most out of the system w/o throwing away more $ (unless it works!).
hysteve
I have used high quality USB cables including a WireWorld Starlight Platinum 7 and Audience FrontRow.  Each brought substantial improvement to my digital setup at the time.  Last week I purchased  a Sablon USB 2020 cable to go between my Wolf Audio server and my Gryphon DAC module and it has far outperformed the ones I previously enjoyed.  
I systematically evaluated USB cables for my ~$7K former headphone system and ultimately settled on some $500 USB. This was cost effective use of the funds for what I could hear. 

My dealer / friend that I trust completely said the biggest difference he has ever heard in an interconnect was an Ethernet cable.

So yes… I would imagine 5% would be a starting place, then try a couple less and more.