From what I understand this blocks ISP YouTube cache servers...which seem overloaded for some, and this defaults you back to Google's data center.
If you have 3rd party router software such as DD-WRT or Tomato, telnet into your router and run these two commands:
If not, you can use this guide to block the ip's on each windows machine: Guide
The first range worked for me on TWC, the second range worked for me on U-Verse, I decide to just block both. This fixed all my youtube problems, no more choppy playback or buffering problems even at 1080p.--
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