That script probably depends on how many IE bookmarks you have and there may be an issue if you have more than a certain threshold.

This doesn't answer why Firefox is so s-l-o-w. Can you address this issue?

I have noticed the same problem after I upgraded to the latest version. I've tried opening in safe mode, disabled add-ons, etc., but no joy. IE works normal speed, so I have to conclude it's a Firefox-specific problem. There are no script error or other obvious messages - it's just more sluggish than it was before.

I'm sorry I can't offer a solution, but you're not alone and, if this is more widespread and enough people mention it, the programmers will be able to fix it soon.

I hope so. What limited exposure I've had to Firefox 10.x, I'd like to use it but not at this sluggish speed!

Thanks for taking the time to respond.

One thing to try is running SpeedyFox: http://www.crystalidea.com/speedyfox

I just tried it and it helped a little, though there are still some choke points.

I've always liked FireFox and found it to be quite stable. This is the first real issue I've had.

I'll check it out. Thanks

I have had a similar problem. Luckily, I have multiple systems running different OS and antivirus solutions.

I experienced extremely slow Mozilla performance occurred after I upgraded to Bitdefender 2012. Performance is fine on systems that are running Norton 360, Avira Internet Security 2012, Kapersky, ESET Nod32.

I googled to see if other Bitdefender owners were having a similar problem, and there were:

http://forum.bitdefender.com/index.php?showtopic=29037

http://forum.bitdefender.com/index.php?showtopic=29258

http://forum.bitdefender.com/index.php?showtopic=17458

I've encountered the warning message "Warning: Unresponsive script A script on this page may be busy, or it may have stopped responding." on all systems, especially when I cleared my recent history / cache.

So what AV package are you using?

McAfee. Been using it for the last 4 years or so. The script error upon first startup after install doesn't bother me. It's the slow performance that does.

Most pages load normally but navigating around on pages is like dialup days.

Say a page has a pick list. opening it up is s-l-o-w-e-r than molassis in January.

I have a fresh new install of Firefox 10.0.1 with no addons or whatever.

I am a SmugMug Pro user and editing my price lists is where IE8 was getting script errors and locked up. They recommended I go with Firefox. Firefox lets me edit/manage my price lists without errors but is extremely slow. I am comunicating with their (SmugMug) support people but haven't resolved these problems yet.

I have had some script error messages like that, but nothing overly annoying - maybe three in the last month and a half. The sluggishness is what is really problematic for me too! I'm not running BitDefender, though it is always possible there is a conflict between the new version of FireFox and anti-virus software in general.

I've also noticed it takes over a minute to open and has high memory usage. Could this be that "memory leak" issue that's plagued FireFox since a couple versions ago? I've never had much of an issue, but I know people who had it so bad they left FireFox altogether when Chrome came out. I'm not ready to join the Google Collective yet, though!

Hifi - do you know how to check the memory use? Control-alt-delete to get the Windows Task Manager, click on "Processes" tab and then sort the "Mem Usage" column to show the top users. If FireFox is running really high, that may be a clue.

Good try but didn't show anything unordinary. FireFox showed 140,xxx but IE8 showed 179,xxx for the same operation on the same web page. Maybe you have something about Firefox 10.x having problems with antivirus in general.

A quick search turned up: http://www.pcadvisor.co.uk/forums/1/helproom/4118075/firefox-10-running-slow/

Doesn't offer a solution, but it seems others (though not all) have had intermittent issues as well. I wish there was some common thread - all running the same add-on, for example - that would be a clue.

I just tried the advice found here and it does seem to have improved performance.

http://howtohacklife101.blogspot.com/2011/05/how-to-make-firefox-faster.html

Cool, but again no help. I tried all the hacks in your last post (http://howtohacklife101.blogspot.com/2011/05/how-to-make-firefox-faster.html) but it didn't help in the manage/edit price lists on my SmugMug page.

I hope these hacks will only effect Firefox.

It sounds like it may be how Firefox is managing scripts or something else on that specific page, since you said it worked on IE8. There is probably some setting somewhere that will fix it, but the trick is which one! I'm not familiar with the website you're talking about. Are there a lot of ads on it? I've found they can slow pages up because they all have to load along with the content you actually care about. I use AdBlock Plus and Webmail Ad Blocker and noticed a big difference in performance. Both are free Firefox add-ons.

No. No ads. I own the site. SmugMug owns the servers. Just weird. Yah, like you said, there is probly a setting somewhere to address this in Firefox but only the shadow knows which/what one.

If it's only in Smugmug, have you tried contacting them. They may have a poorly optimized piece of JS on their site or it may be interacting badly with some javascript engine changes that were made in Firefox 10.

Yep. Asked them if they had others with this same prob. They said they are watching their forums. I was hoping they would be more aggressive and tackle the programing glitch they have.

Thanks for the comeback

Me too. Firefox has slowed down and is now so slow that pages time out, functions don't complete, and the frustration meter maxes out. No, it's not my machine, it's Firefox. Appalling crawling....

I think the MAIN reason why developers still use FF is for firebug. I know that's the main reason why I use it. But Chrome has a pretty decent tool as well. I'm glad I found this thread because I thought it was my box as well. I actually am beginning to hate FF as well. Even firebug isn't luring me over to it as much. If it's not fixed soon, I'm leaving it alone, only as a testing browser, but not for anything else.