If you stream music from the internet, I can't recommend this more highly

I had been using a Roon Nucleus to stream Qobuz, with my Chord Qutest directly connected to the Nucleus. I thought I was getting pretty decent sound quality. And then I got a marketing email from Small Green Computer touting some of their optical gear. The basic idea is that normal cables and connections used to stream from the internet pick up noise of one kind or another (radio frequencies and electromagnetic something or other). But fiber optic cables and their connections/interfaces do not. I don’t know anything about anything, but it made theoretical sense to me, it wasn’t a huge amount of money ($1,400), and with a 30 day return policy I figured I could always return it if I didn’t hear any improvement. Well, I didn’t just hear a slight improvement; it was like turning on the lights in a dark room. Much greater clarity and detail, much better micro and macro dynamics, better timbre to acoustic instruments -- overall just more lifelike. Two quick examples: I’ve listened to some of Steely Dan’s top songs 100s of times over the course of my life, and this is the first time I’d ever noticed a particular and very subtle sound characteristic of Fagen’s keyboard in Babylon Sister. It’s hard to describe, but it’s like there’s a slight sound of air being exhaled by it. The other example: the specific timbre of whatever percussive instrument is used at the beginning of Copeland’s "Fanfare for the Common Man" (a recording by the Minnesota Orchestra). There’s more of a metallic sound than a drum skin sound to it that I didn’t know was there before. The metallic sound starts in the center and then projects out and to the sides, like a wave washing over you. Anyway, I’m just thrilled about having stumbled upon the whole "optical" thing and felt obligated to let others know about it. If you stream music over the internet, I highly recommend giving it a try. (The product I got was the opticalRendu, with the linear power supply option, and the Fiber Ethernet Converter Bundle option.)
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A couple of years ago I read an article by Michael Lavorgna at AudioStream that presented a method of optical isolation involving two TP Link Ethernet/Optical converters and a short optical cable.  Total parts are less than $100.  I run the Ethernet from my router into a Bonn switch and then into the above optical isolation set-up and then a very short Ethernet cable from the second optical converter into my server.   I believe this provides a subtly smoother presentation.   
It does not compute imo that simply replacing the ethernet cable by optical, with its conversion, would negate the need for reclocking, etc. One seems to be for the purpose of eliminating the noise in the transmission, while the other is for the purpose of altering the wave form. 
That is how I see it too.
Except that ethernet carries no audio clock information, and proper layout will easily eliminate modulation of the digital power supply /ground from entering the analog section.
The opticalRendu is a streamer you attach to a USB DAC. Some DACs have build in streamers but most don’t.

The Rendu takes music from Ethernet and sends it down the USB cable to the DAC. For the DAC to sound its best this USB signal needs to be free of noise and jitter.

So I’m just not sure how "cleaner" ethernet packets going into a devices memory chips (cache) would improve the sound.

We are not "cleaning" ethernet packets. There are digital and work the same if analog noise is present or not. We are remoting the analog noise from the Ethernet cable and keeping out of the analog stage of your DAC.