Plugin-container in Firefox 4; High CPU and Graphics Switching Problems and Workaround

Question

I recently upgraded to Firefox 4, and unfortunately, I've had many problems running Firefox under OSX on my Macbook Pro.
The first problem I came across was that Firefox is now hardware accelerated. This should be a good thing, but due to the way Apple has implemented graphics switching, Firefox caused the discreet graphics card to be used (as seen with GFXcardstatus)
To prevent this, I went into preferences, and disabled "Use hardware acceleration where available" under Advanced>General.
But my problems didn't stop there. Now, it seems Firefox has decided to run plugins such as flash under a separate process called plugin-container in order to protect the browser from plugin crashes. This is a good idea (I believe Chrome and Safari do the same), but even with hardware acceleration disabled in Firefox and Flash, plugin-container still triggered the discreet graphics.
This would actually be acceptable if plugin-container was terminated after I navigated away from the page with the flash content, but this is not what happens. Instead, plugin-container keeps using the high-powered GPU until Firefox is closed.
At this point, I thought that I'd try to force the computer to only use integrated graphics (using gfxcardstatus), but then I discovered another problem:
The plugin-container process was using large amounts of CPU time when flash content was visible in the Firefox window. Typically, viewing just a static flash ad would cause plugin-container to use about 60% (in addition to firefox using about 20%, that means 80% total). Obviously, this was a battery life problem.
After all of this I think I found a temporary workaround, but there are clearly problems here that need to be resolved by the Firefox developers. There are many non tech-savvy users who are no doubt experiencing poor battery life from these problems.
'''My Temporary Solution'''
1. Disable hardware acceleration in Firefox in Advanced > General
2. Disable hardware acceleration in Flash by right clicking a flash element, clicking settings, and then unchecking "enable hardware acceleration"
2. In about:config, search for dom.ipc and set all boolean values that appear to false. This will disable Firefox's plugin-container process for all plugins.
(At this point, if you restart Firefox, Flash will not work at all)
3. Set Firefox to 32-bit mode by getting info on Firefox.app and then checking the "Open in 32-bit mode checkbox"
4. Restart Firefox. Flash should be working with reasonable CPU usage (I had something like 20% with static flash ads as opposed to 80% before), plugin-container will be no more, and your Macbook will no longer switch to discreet graphics for Firefox or Flash.
'''UPDATE:''' It seems that firefox still sometimes causes a switch to discreet graphics for certain flash elements (video players mostly). Also, I've still seen some cases where flash elements are using large amounts of the CPU, even when they are not in the current tab.
I hope this was helpful to somebody, and if anyone has a suggestion for how to make this workaround obsolete or better, please respond.

Answer 1

Ive downgraded from FF4 to 3.6 at this point. The CPU usage is out of control on OS X.