How can different CAT5/6 cables affect sound.

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. 

@audphile1

I have heard that Meitner makes great gear, I wanted to listen to their DAC when I bought my K01XD but they had sold their demo!  Also your speakers and amp are known for their resolution and transparent nature, perhaps revealing differences that my system does not.

I have been researching (actually Googling, using multiple search phrases to test the responses) and have found some interesting stuff about streaming services.

There are differences between the services, when a recording is made it is usually recorded at -8 to -12 dBFS (pop/rock/etc) to allow some headroom.  The master is then mixed close to 0dBFS.  Classical music recordings are processed less.

Qobuz, Tidal and the major streaming services then reprocess the data of each track to their house loudness level (e.g. -16dBFS peak), which varies across the services. Their intent is that all tracks should be about the same loudness.

Presto is a very niche player in the streaming business, being classical and jazz only (34,000 albums, not the millions of the big guys), and does not do that level of processing.  Their primary business is selling vinyl, CDs and downloads.  Hence Qobuz and Tidal streaming services may sound different from each other, the data they stream is different from the data in the master, and is different from a rip.

Presto's target is that a stream and a download should sound the same, and should preserve the dynamic range of the material, which might explain my not hearing a difference between the two sources in an earlier test.

I am interested in seeing your thoughts on this, I have found your responses most interesting and thought provoking.