During downloads, the top command shows the Firefox process at 100% CPU. Yesterday I tried to download an .iso image. After a few hours the Firefox window would not refresh nor would it respond to input. I tried the wget command. It used negligible CPU time and completed in 28 minutes.

This problem is easy to reproduce because it happens every time I download a file in Firefox. It also happens when I use a fresh profile to run Firefox without any extensions or plugins. Any idea what to try next?

This is Firefox 3.6.12 on Fedora 14.

Firefox for some reason lately has been having these problems with its add-ons lately that have been causing it to go zombie and act unpredictably. It could a Java script from a website that is causing firefox to do tremendous calculations for no reason besides what the script tells it to do. Better example with whats been happening with some computers is after you have exited from firefox for so long this windows xp looking window will pop up saying you have a virus and plays this fake video looking thing so you download there virus written bloat-ware for windows.

I can no longer reproduce the problem. It is possible that it was caused by a misbehaving name or web server.

As I understand Firefox 4 is supposed to have fixed the crazy add-ons problems. I have had reports that flash was the one doing it. In said forum they were saying flash sets all of its threads to high priority causing it to take much of the CPU power.