I would like to point out, that for me at least, this hasn't happened in a while (I usually run with 5-10 tabs open for weeks at a time).
It only ever happened with very specific websites.

And, to answer another question: I think I experienced this on an AMD desktop years ago, but I so rarely use desktops that I can't be sure that was actually the issue. I have run into it on three laptops that I can think of.

Luke