I have dbillion cat8 at the in coming signal from modem to router and PC . In comparison vs that of Cat 6 flat unshielded to my gear the Cat 6 booted up faster even though the Cat 8 has the highest overall speed (up to 40g tested) but pixelated a bit when used to Nvidi shield before locking in fully but tested to the PC its rock solid with a substaial speed increas over cat 5 I previously had in place all cables are carefully of course . In the end I went the safe route to my gear using a TP Link 2000mbs powerline adapter with unshielded Cat 6 to my shield and AVR . Why? Pontentialy the grounding scheme reqiured for Shielded applications can be tricky, if there is more than one grounding path from your home, you could be turning what you think is a shielded cable into an antena behind your gear!
That's all I know about it for now!