The only way to stop Firefox from taking up all the CPU is to close it and open it back up. Doing some tweaking with the About:Config doesn't change much except that it takes a bit longer before Firefox gets to over 100,000k. This is definitely some kind of a memory leak where the more tabs you open, the worse it gets. Closing the program and re-opening it starts it back to a lower level.

I am now using a somewhat less bloated and functional browser that doesn't nearly get as big as Firefox. It's called OffByOne ( http://www.OffByOne.com )and for many people, they won't like it because there aren't many features and many plugins are not supported. But, for simple browsing, it's fine.

I actually love how much less CPU and memory it uses.