As far as I’m concerned, old threads can still point to issues that are still existent.
This is the case when you have the same problem. In your case, this thread is unrelated to your problem.
As time goes on, you require more bandwidth to use Twitch.
This is not necessarily true. I’ve been around in the JTV/Twitch community since 2010. Apart from the shift into HD content, there has been no significant changes to bandwidth requirements in the past 3 years.
Your maximum sustained Internet speed has little significance for the rate at which you download video content from Twitch.
In other words, the reason you’re buffering is usually not because of your Internet speed, your local network, or Twitch. It’s the path by which your Internet connects to Twitch.
Think of the Internet as a series of pipes. These pipes can get easily clogged. Your ISP, Internet Service Provider, is responsible for finding you the best set of pipes for you to use (which is called routing). If you’re buffering, it’s because a pipe is clogged somewhere in your route to Twitch.
This is an issue for you to work out with your ISP, since they are generally at fault for these congestion issues (they save money by choosing lowest cost routes).