Ethernet cables

So I've been streaming for just over a year (I'm really an analog guy, listen about 75% to my TT set-up). Been listening to Roon/QoBuz via my MacBook Pro thru a Bricasti. The Bricasti is hooked-up via a Ethernet cable to an Xfinity "POD"  which works well. Yesterday got in a Roon Nucleus and what a great sonic improvement! Very happy. But here's the question. I'm using a very good Ethernet cable from the Bricasti to POD but how important is the Ethernet cable from the Nucleus to the switch? Personally I haven't done much comparisons with Ethernet cables. 
(Dealer disclaimer) 
A lot of people here are impressed with the optical Rendu that reportedly removes noise and significantly improves sound quality, so that may be something to consider.  Best of luck. 
Check Network Acoustic. I have the Eno system and the result are phenomenal.....everything more
Hi sksos: I found this review article helpful  In the conclusion section they determined that the cable from the modem to router wasn't important. I had a combination of Supra Cat8 and SOTM Cat7 in my system. I recently replaced the Supras with the Viablue cables.  They are a bit more money, but they are a definite upgrade in sound quality from the Supras (better frequency extension and the highs really sparkle without edginess). The SOTMs are for sure the best, but at a price. Good listening. Jeff
Hi yoby, I have the same via blue cable from my router to the SotM switch se with master clock inside. But from the switch I can only strongly recommend the ENO system from network Acoustic !!!!!
I also saw a big difference when you put a linear power supply to your router/modem.
I'm about to pull the trigger on a  Bricasti M3 with their optional Network Interface. 
I have concerns about a difficult ethernet cable installation from the white Xfinity xFi Router/Modem located in another room after reading this FAQ.

I have an xFi Pod with the two ethernet jacks but isn't that ultimately still a WiFi connection?

Not very digital source savvy from over ten years with just a Mac Mini WiFi to a Squeezebox Touch and a Metrum NOS Mini.

I have an xFi Pod with the two ethernet jacks but isn’t that ultimately still a WiFi connection?

It is, but hard wiring the M3 to the xFi Pod with an ethernet cable will be an improvement over WiFi from the xFi Pod to the Bricasti: better signal stability.

If your WiFi strength is good at the xFi Pod, then you’re good to go.

Later, you might consider hard wiring the xFi Pod to your WiFi router (or a network router), if it’s not too much trouble.
Later, you might consider hard wiring the xFi Pod to your WiFi router (or a network router), if it’s not too much trouble.
So, the DLNA (I don't know what that is) they say won't be supported over WiFi will function?
But in the end an uninterrupted ethernet cable from the modem/router is preferred?

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@m-db I'm using the Bricasti M12 exactly like you would use the M3 into a white Xfinity "POD" that has the 2 Ethernet ports underneath. My Xfinity Router/Modem is in another room and I have a Roon Nucleus hooked up to a switch which is then hooked into the Router/modem. The Bricasti works flawlessly and you I choose my songs via either an iPad or my phone. Either way no problems.

(Dealer disclaimer) 
So using a Roon Nucleus or another streamer/server is an improvement with the Bricasti M3, even an M3 with the Network Player Option? 

In either case, is this due to eliminating the Mac or the PC from the system?