Ethernet patch cable 5e with cat 6e

The basic difference between Cat 5 and 6 cables is bandwidth. A Cat 5 is capable of 100 Mbps and the 6 can do 1,000 Gbps. However, 5 is more than adequate for the transmission speed needed for audio playback, so that particular item shouldn't be an issue.  However, if you are getting what you perceive to be a sonic benefit from the shielding of a Cat 6, then you'll be giving up some of that if you hook a 5 in series with a 6.  However, EMF/RFI is not an on/off or black/white phenomenon. There are shades of gray in terms of how much isolation each cable offers. I'd suspect that while a 5/6 combo run is not as insulated as an all 6 run, it would probably be better in this regard than an all 5 run.  For me, it is not something I'd spend much time worrying about.  However, I know others can obsess about such details, so it is up to you to figure out what works for your setup. 

HD Video streams at about 5 Mbps and ultra-high video (4K) needs about 25 Mbps. So the Cat 5 spec and 100 Mbps connection would still work fine for that. The only way you might get in trouble is if you have multiple users all streaming different 4K video sources at the same time. 

A cat 5 would probably work fine, but does it impair and reduce quality of the audio and video being streamed? What a cat 6E work better? And longer-term I guess it would be better.

We know the video Signal may be fine, but the audio signal which has always been compressed in the past is now receiving more attention toward being uncompressed and with this would a cat 5 not work as well since many of us Herein are using a very revealing soundsystem when watching movies.