Wow. What a disappointment. I came on this thread to see what the OP found RE which Ethernet cables worked best for him and for other's suggestions, and instead I mostly had to scroll through 10 pages of "discussion" on whether I should care.
While I await further actual discussion and advice on which Ethernet cables perform better, I do enjoy attempts to explain how things actually work to produce a given outcome or experience, rather than passionate recitals of theory for why they should not. As usual, I do find @almarg 's comments and explanations useful in this regard, particularly this excerpt from his post on 4/20/2017:
"in a post in this thread dated 3-28-2017 I suggested the following experiment to some of the others:
Tune a portable battery powered AM radio to an unused frequency, with the volume control set at a position that you would normally use. Bring it close to an unshielded ethernet cable on your LAN, while the cable is conducting traffic. You may be surprised at what you hear.
When I do that with the unshielded Cat5e cable I have on the LAN in my house, while the cable is **not** conducting any large amount of traffic, I hear increases in static from the radio when it is as far as 2 feet from the cable. Keep in mind that an AM radio is designed to just be sensitive to a narrow (~10 kHz) range of frequencies in the lower part of the RF region (nowhere close to frequencies corresponding to the bit rate of ethernet traffic, much less to the frequency components that constitute the risetimes and falltimes of the signals), and to have a sensitivity measured in microvolts. And for audio we’re dealing with microvolts as well, but without the benefit of the radio’s narrow band filtering. For digital audio if 2 volts corresponds to full scale the least significant bit of a 16 bit word corresponds to about 30 microvolts. And the least significant bit of a 24 bit word corresponds to about 0.1 microvolts! And perhaps more significantly there are jitter effects that will arise as a result of noise whenever D/A conversion is performed, of course. And this experiment just involves radiation of RFI through the air. Not through what would seem likely to potentially be much more significant unintended pathways for digital noise, such as grounds, other wiring, and parasitic capacitances within the components.
Regards,
-- Al"
This has me me wondering if at least part of the issue with Ethernet cable design execution and performance is to curtail the bad things that unshielded or poorly shielded Ethernet cables may do to other low level signals in nearby analog or other digital cables or their connectors in the vicinity of a shared piece of equipment. Could it also be that the digital signal in the Ethernet cable could be corrupted in some audible way by interference from high current or high frequency signals in the vicinity of your gear stack to the point that it defeats buffering or operates on the signal at some point downstream to inject noise in digital or analog signals. This may result from a number of parameters including the quality of other critical cables in use, wireless signals in the area, the physical layout of equipment boxes and the cables behind your gear, and as Al notes the design and behavior of the gear itself with respect to external interference. All this without even invoking the design trade offs and opportunities for noise generated within the connected circuits themselves, as described by Al.