My Firefox also recently upgraded itself and all its plug-ins. Now I can't even play solitaire because the plug in container module uses 80 to 100 % of the CPU even if I'm not Playing, the computer freezes up and takes forever to do anything. Can't imagine why Adobe would create such a resource hog when everyone else is trying to come up with ways to save the cpu usage. When I end The Plug in container module in the task manager, my cpu usage drops to nearly zero and everything works fine again.

When Firefox recently upgraded itself, it added a new feature called the "Plug-In Container", It is supposed to protect the browser when a plug in crashes but it is the source of the CPU usage and the computer freezing. Java does nothing different, but If I stop the plug in container process in task manager, the computer instantly starts going again and the CPU usage drops to around 10 to 15 percent. Got to have a flash player but the new Adobe is just too much of a resource hog. It uses nearly 100% all the time, even if your not doing anything that would need a flash player. Anyone know of another compatible Flash player that works on Firefox 3.6 or is it time to go looking for a new browser? Adobe has pretty much disabled firefox.

I found that by taking out the plugin container in the mozilla file, uninstalling flash, and reinstalling flash, that it reduced the cpu usage by 1/2. But this only worked on the computer that also has the Opera browser installed. For some reason the flash installs in the opera browser but firefox still utilizes it. In the add ons in firefox it doesn't even appear yet all my flash sites load and play just fine, no more cpu issues. Hope this helps!

I have found exactly the same thing. I now have to use Chrome to open my Conceptis puzzles ( which use FlashPlayer) and even watch movies on Netflix, as Firefox won't open that up. Uses up to 98% of CPU even after I've shut it down, usually uses from 0 to a high of 29% when operating normally. I love Firefox, but...

I have been a loyal Firefox user since version 1. I installed version 4 two days ago, and now this CPU hogging problem is creating major issues for me. I have tried the fixes above, but they haven't helped. In addition, the links on this page ([[http://kb.mozillazine.org/Java#Multiple_Java_Console_extensions]] come back with Error messages too. What's happening with Mozilla? I don't want to start using Chrome as my default, but that may become necessary if this CPU memory issue remains.

Hopefully my tests here might help towards a solution:

I installed a NEW version of firefox portable 7.0.1 - completely empty- and tested with it. (I followed a document I found on dhdaily.com on how to install it in parallel.)

I made the following discovery: Firefox runs normally IF you only open up one tab. If you open up more than one tab at a time, EACH TAB must complete IN ORDER before the next one works. So site 1 has to load to completion before site 2 can complete etc. If any site is slow, then the rest of the chain is slow.

As a test, I opened up my EBAY account and, while it was loading, opened up my feedback in a second tab. The second tab would not even start until the first tab page completed.

I then closed and restarted Firefox and opened up three different webpages in three tabs: www.google.com www.refdesk.com www.microsoft.com. Again google had to finish before refdesk would load. Refdesk, being large, stopped Microsoft from completely loading until it finished.

So it seems to be some sort of thread balancing issue involved where the first tab is not playing well with subsequent ones.