How can different CAT5/6 cables affect sound.

@retiredaudioguy to your point my Meitner MA3i DAC has a pretty high quality built in network card. I’m using it as a Roon endpoint so the only connection into the Meitner is Ethernet cable. This DAC replaced Aurender N200 and Bricasti M3 combo where I was using a USB cable from N200 into Bricasti DAC. 

I stream from Qobuz, Tidal and a local library of CD rips I have on SSD that is mounted inside Roon Nucleus One. I can also stream using Tidal Connect, Wobuz Connect and Mcontrol app. 
I can hear the difference between Tidal, Qobuz and CD rips streamed using Roon. I can also hear that the Tidal Connect sounds different than streaming Tidal using Roon. Same goes for Qobuz Connect. These methods sound similar to using Mcontrol app (upnp). It’s very interesting. It’s not just bits are bits. 
 

@audphile1 

S/PDIF can carry DSD when reencoded as DoP, as you pointed out. However it can only support DSD64, which is carried within a 24/176.4kHz PCM signal, essentially equivalent to 4 times Redbook (since DSD64 is 1-bit resolution at 2.8 MHz, v 16 bit at 44.1kHz, or 705.6 kHz, for Redbook).

By that token, DSD128 and DSD256 over DoP require 384 and 768 kHz PCM signals, respectively, both of which are beyond S/PDIF capabilities.

Additionally, not all DACs are DoP-compatible, so all in all there is little to recommend DoP unless specific limitations rule out native DSD. That's why I didn't mention it.

It's probably fair to say that DSD is best enjoyed with digital chains that natively support it end-to-end.

I see you’ve been doing some research now :)

Can’t recall hearing any difference between DOP and native DSD with Bricasti M3 when I had it.  
In any case my Meitner DAC upconverts everything to DSD. Interestingly enough it doesn’t support native DSD which is totally fine as it sounds great with DOP and any format you throw at it. 
 

If you have a large library of DSD rips and having a DAC that supports native DSD is a piece of mind for you, go for it. I do most of my listening streaming. I do occasionally play DSD, CD rips and even physical CDs which is cool if I feel nostalgic but overall there really is no sonic benefit in it. 

I am planning to build a setup that upsamples all inputs to DSD512 in real time and feeds the signal to a simple DSD-only DAC.

I can’t speak to the sonic benefits, if any; it’s just an experiment I am wanting to try.

PS Audio and EMM Labs/Meitner upsample all incoming signal to DSD. Latest EMM and Meitner DACs upsample to 16xDSD internally in real time. That’s DSD1024. 
PS Audio DSD MkII upsamples to 20xDSF. 
 

I believe Playback Design upsamples to 4xDSD.