It seems to get worse the more tabs I have open.

LtPowers - Let's try some standardization. You have ver 7.0.1 so you can go to the App Button, [menu button], Help-> Troubleshoot Information -> Copy all to clipboard, and then open a notepad window - or your favorite text editor - and paste the log there. Look at it and see if it suggests ay answer to you. If not, repost the problem - with the log appended. That way you give notice of hardware and OS, so that users with similar configs, or knowledge, can help. It might be you have too much other stuff loaded for your system's chip memory. If you get to disk caching and swapping, things get really slow. It might be that addons are in conflict with the new version or with each other. That is why the addon listing might help an experienced user to give help. I use XP SP3, and am familiar with the Task Manager window there. It tells me total memory and memory commitment. For instance, now, FF 7.0.1, taking up 805 +/- meg due to the config and large number of windows and tabs open. It says I am using 1.6 Gigabytes of 3.2 [only 2 gig installed memory, the remainder is disk caching, where I can slow way way down if I get there]. I have Chrome open too, several addons, taking memory. I closed Chrome, and it drops to 1.3 gig committed. From experience 400 - 500 meg are take up in system resources, after a bootup with no applications running. So my slowness now is from overstuffing the browser - a problem I had with 3.6 too when I went hog wild on open stuff and addons. If you can check such things on your hardware/software it might help. The big thing, posting a troubleshooting log with the problem is my first helpful idea. Others besides me may read that and have helpful suggestions. Posting the log will also show whether you are disabling addon compatability checking. If you do that - as I do - you are at risk of weird things showing up on upgrading.

I am having the same problem, which started early this morning and has been persistent. I have also uninstalled/re-installed FF, but still have problem.

Eric, I posted that information with the original query. You can see it over to the right of my question; just click "More system details..."

I know what disk caching and swapping looks like, and that's definitely not what's going on here. It could be an add-on problem; I'll look into that.

You can try to decrease the value of the pref network.http.max-connections from 255 to a more modest setting of 30 as used in Firefox 3 versions.

To open the about:config page, type about:config in the location (address) bar and press the "Enter" key, just like you type the url of a website to open a website.
If you see a warning then you can confirm that you want to access that page.

• Use the Filter bar at to top of the about:config page to locate a preference more easily.
• Preferences that have been modified show as bold (user set).
• Preferences can be reset to the default via the right-click context menu if they are user set
• Preferences can be changed via the right-click context menu: Modify (String or Integer) or Toggle (Boolean)

See also:

• http://blog.bonardo.net/2011/09/30/is-your-firefor-freezing-at-regular-intervals

Thanks! I'm not sure why that fixes the problem, but it does. Weird!

Was having related problems, updated to developer release 8.0. Seems fine and fast, now. Checked the pref, and its default is now 30.

But having trouble with tabs; they won't select and drag any more!

I might have discovered the solution without starting over with all your places and bookmarks.

Right after i installed 7.0.1 over a week ago,every 10-30 min When i would be watching videos online, it would freeze for 20-30 seconds. Firefox would say ( Not responding) both firefox and the plugin container process would be very large memory files. I tried to go back to Firefox 5.0. No avail it would still freeze.I tried to disable the plugin container . no good. I tried to adjust memory or cache or plugin settings in “about:config”.Nothing fixed it!

I finally discovered why my Firefox 7.01 was periodic hanging fix. It is something to do with some of your personal files. download this this add on and install it https://addons.mozilla.org/en-US/firefox/addon/places-maintenance/

or you can Google "places maintenance Firefox"

After you install the add on, restart Firefox.go to "tools", then "add ons" and then click “extensions” tab ,then click' options" on the "places maintenance" entry. choose "ALL' or just "expire" and hit "execute", then wait until its done., restart Firefox. should be fine then and all my bookmarks, customizations ,settings, and history stays untouched!

After i did this my Firefox did not freeze once for over 3 days straight. Might not work for everyone. I already read that Mozilla is aware of the problem and are working on a fix it in the full version of 8( the 8 beta did not fix the problem for me) . But they said this is a good temporary fix at least,( might be permanent)

For me at least ,Firefox works fine in 7 now. perfect actually.And many people i saw on similar forums had similar problems.

Enjoy. Hope this helped