If you have ATT fiber but youtube buffers there is a fix (Chapel Hill: chapel)

[Bpobill]

I have had att fiber for a while now and love it. Extremely fast but youtube kept buffering the last couple of months. I googled it found other complaints and there are two fixes. Disable ipv6 and use Google dns or open dns. Im not a network engineer but googled how to do it on a mac and it was extremely easy. Changing the dns from att to google solved my problem. I can load 4k videos without any hiccups now. The buffering started a couple months ago for me. All other websites work perfectly fine.

ipv6
How do I disable IPv6 on Mac OS X? | Help & Support | The University of North Carolina at Chapel Hill

Google dns
https://www.howtogeek.com/howto/3879...or-google-dns/

Others reporting issues.
https://forums.att.com/t5/AT-T-Fiber...g/td-p/5041348

For a windows computer you are on your own but i'm sure it's easy to find on Google. I get 900/900+ on wired and 400/400+ on wireless at home. I also updated the dns on my iphone and that is now better as well.

[K4GPB]

For Windows, run NAMEBENCH to find the best DNS to put in your computer or router's settings.

Really works!

https://www.howtogeek.com/howto/1637...ith-namebench/

[zinner]

DNS speed doesn't directly affect the speed/buffering, but it does affect which cluster of server you reach for. So changing your DNS or disabling/enabling IPv6 (which will also affect DNS and server cluster) might help you out. Probably the network peering point with google is just full at peak times, so it might not help at all.