After several updates to Firefox and Chrome, both became slow and streaming impossible. I normally blame this sort of thing on add-ons but in this case, I tried adding Adblock Edge (https://addons.mozilla.org/en-us/firefox/addon/adblock-edge/) to Firefox. Instantly, Firefox started streaming again. I still had one nasty ad at the top of http://rt.com so I right clicked on the add and blocked ||googlesyndication.com^.
I understand the desire to monetize the web but as the ads disappeared, I noticed some sites whining that I was running an adblocker. I heard Clark Gable whisper in my ear the words of Rhett Butler "Frankly, my dear, I don't give a damn"..
Adblock Edge is a "fork" of Adblock Plus without the "whitelist" feature (and possible some others). There is no Adblock Edge version for Chrome (Adblock Plus is available. I don't use Internet Explorer so you are on your own in that case.
I will keep Chrome around (and Opera too) but for performance reasons alone I strongly recommend Firefox with Adblock Edge. So strongly, I suggest you try Firefox before chasing performance issues. I am mixed about the betas. The frequent updates can be annoying with little upside.
This brings me to the issue which provoked my attention to performance. I am a news junkie. That is my mother's fault. She was not the sort to "suffer fools gladly". Although I value equanimity highly (Emerson) and my world view is conditioned by the likes of Jesus, Emerson, Voltaire and Proudhon, a depend on two "cranky" news sources - https://rt.com (admittedly funded by Russia) and https://democracynow.org (admittedly funded by cranks like me).