same problem viSTA 64 ... slow pages sometimes even times out. Only change was the automatic update to 3.6.6

Checked with son (laptop with Vista) .. he upgraded to Firefox 3.6.6. He thought the slowness was his ISP at first, everything on the browser is very slow. Can't watch video, breaks up as it's now operating fast enough.

We need a fix soon. I hate to have to leave firefox behind.

Not only is it slow to run for me, it takes FOREVER to start up!!!

Same problem with my Mozilla 3.6.6(again an auto update). Deleting Mozilla profiles, clearing cache didn't helped. Disabling JavaScript (which makes page load faster normally) didn't even helped.

This slow down is quite noticeable compared to the version 3.1

One peculiar thing i noticed, when there is no existing profile(all deleted) for first time it loads with amazing speed... but as soon after first load (which creates again a new profile, if no existing profile found) it becomes slow again...

I Hope Mozilla guys already working... because i have to unwillingly use alternatives.

-Jalaj Chhalotre

Same problem here, plugin container takes a lot of cpu (10%) while playing youtube, clips take a while to load, bad update guys...

Not only does 3.6.6 slow down my browsing on Firefox - but it also seems to have slowed down my entire PC. I'm running XP and everything was running just great until the 'upgrade.'

The worst is trying to watch videos - on YouTube or even off my hard drive with FF running. Should I just switch to Safari?

I also noticed the Plugin Container taking up a ton of CPU capacity. Do we need it for the Plugins to work? Or can I disable that application?

If anyone comes up with a fix - please post it here.

Mine has become unusably slow. I am OSX 10.6.4 and FF 3.6.6. I am getting nonstop hangs/stalls/freezes. I am constantly seeing the spinning pinwheel. This is even for sites that don't have anything special on them (like Flash). It even freezes my entire system. I have had to force quit the application a number of times now.

Terrible update.

Similar problem here. After the update all flash video's play like crap. Youtube jittery, vimeo even locks my pc. I switched to Chrome until they release a fix for this. It's unbelievable!

I know this will make a lot of people mad, but for once, I think IE is actually faster than Firefox.

I guess this gives me the opportunity to try out another browser like when I got mad at IE and switched to Firefox!

It Seems Like Flash Player is the main problem. I am not sure whether it will help you or not but I uninstalled Flash Player and finally I can read the news again and browse faster.

I am a computer newbie and do not know much about computers.

I'm throwing in the towel on this one...

Tried going back to FF 3.6.4: same problem.

Tried re-installing FF 3.6.6 with no open tabs, per Medlir: same problem.

Tried uninstalling Flash 10 and going back to 9: YouTube and other video sites said I need the latest version. So I had to go back to 10.

Tried Google Chrome for Mac 10.5+ - same problem.

Tried Safari 3.1.2: Freezes on YouTube videos. I may try to upgrade to 4.x(?).

Or I could just go back to smoke signals, Pony Express, or some other analogue method of communication that doesn't offer "improved updates"...

Is is Flash?

Is if FireFox?

Who knows.

Are we all annoyed??? YES! Come ON Mozilla!

I have the same problem on windows 7. Every time I try to go to a site or do a search, I get a not responding message for about 10 seconds, and then the page finally loads. SO ANNOYING. I am now using internet explorer for the first time in a few years.

Same problem here since upgrading from 3.6.4. Various websites will hang for 10 seconds or longer before loading. It's frustrating to say the least.

Please fix it Mozilla!!

Yup, Chrome fast, IE fast, Firefox... slow. Thanks to my ISP for showing me how to change browsers.

Same problem - Mac OSX 10.5.8 -AND- VISTA. Removing plugins didn't work; will try the beta thing when I have time. For now I'll switch back to Safari.

Ditto, slow webpage load up and sometimes random disconnects.

I think I fixed the slowness, for some reason my "connecting setting" was set to use system proxy settings. I switched to "no proxy" and it's much faster now.

what a joke. firefox is running as if it's processing something. the cursor indicates busy/pointer all the time until i close the damn firefox.

firefox? firefix this!

The same problem here, on Win XP SP 3.

My problem is obvious when opening a page with a lot of Javascript and AJAX requests. The CPU usage rate stays high for a minutes after everything(including rendering and postprocessing) is done.

No addons installed, no Flash. Worked fine in 3.6.4. Works fine in 3.5.1.

Dank verbesserter Sicherheit, Stabilität, Anpassbarkeit und mehr, wird der beste Browser der Welt noch besser. das wahrt ihr mal , das ist ein witz was ihr macht , ändert das auf den schnellsten weg , ansonsten wechseln eure browser und das wollt ihr bestimmt nicht , seid dem ihr 3.6.4 eingeführt habe läuft nicht mehr , 3.6.6 bringt überhaupt nichts , tut endlich etwas !!!!!!!!!!!!