ETHERNET CABLES

CAT8 is 22awg - the thickest wire of the CATs and therefore arguably the best durability.  It also has optimum shielding and twists but maybe not much if any different from CAT7.  It is by far the fastest but that speed is not needed in a home environment so the only reasons to pay more are for the extra copper and the shielding.  

@kennyc

What you are saying is technically incorrect.  The data is encoded, such as using PAM constellations, meaning the digital signal (1 and 0) are converted to a multilevel signal such that each transmitted symbol represents more than one bit.  As the signal is transmitted over the channel, it starts to appear as an analog signal due to the nature of high speed transmission and the channel.  This can be seen as eye diagrams.   The data does not ride or sit on an analog signal.  Just the opposite, the data is the signal.  Upon receipt at a receiver, the voltage of the signal is detected at specific time and that voltage is compared to numerous thresholds.  The signal is then re-created based on the voltage value in relation to the threshold to re-create the PAM signal.  For example, if the threshold are 0, 1, 2, and 3 in a PAM4 system, and if the received value is 1.1, then the signal is re-created and a 1 value is output.  The noise or timing error that causes the received signal to be 1.1 instead of 1 does not have any impact after slicing (quantization).  If the received signal is 1.4, it is sliced to 1.  If the received signal is 2.7, it is output at a 3 from the slicer.  Again, that noise or timing error does not have any impact.  The signal is recreated and the noise discarded.  The PAM4 signals are then decoded back to 1s and 0.  This is a good link to read.  

Best of all, the bit error rate of the home ethernet networks is amazingly good.  There are CTLE, FFE, DFE that all clean up the signal to correct channel degradation.  Plus, there is error correction such that each packet includes a error correction data that is used to detect and correct errors. And if, in the very rare instance, an error is not correctable, the packet will be resent and filled into the buffer of the streamer.  A typical bit error rate is 10 to the minus 13, which means that for every 10,000,000,000,000 bit sent, there is 1 error.  People do not hear this.  

Even if there were issues (which there are not) between the steaming source, which could may be an another city or state, and your streaming box, the last 3 feet inside your house is the least of your worries after the likely awful path the data has already taken for the miles or hundreds of miles to get to you.  And, over ultra short 3 foot link, there is so little signal degradation that we should not even be having this conversation.  I encourage anyone to correct any technical errors I have made to advance the conversation and improve the accuracy of this forum.  

It never ceases to amaze me how digital experts ignore RMi/EFI and ground level distortion. The issue isn’t at all about lost bits but rather about these distortions affecting timing and the subsequent D/A conversion. That’s why cable shielding and the quality of the conductors (dependent on purity of the metal) have such a big influence, The more distortion is travelling along the cables the harder the subsequent error correction circuits have to work, which in turn results in additional timing errors, not lost bits! And accurate timing is crucial for transmitting the spatial and attack and decay information in the analogue domain.

I like to use this little device for grounding my shielded Cat cables, when the piece of equipment the cable is being connected to doesn't provide a true earth ground.

Ethernet grounding adapter kit

Since we're on the subject, and even though Cat 7 or Cat 8 cables are not mentioned, some may find this article informative:

What makes a good Ethernet cable for audio applications?

Here's what audioquest has to say about one of their lowest quality ethernet cables. This is the one I'm positive I heard an audio performance improvement on. It was easy for me to perform numerous quick A/B comparisons, when switching back and forth to my standard Cat 5 patch cable, and this Pearl. Call me crazy, but I know I heard a sonic improvement.

audioquest Cat 7 Pearl cable