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How to Make Firefox Load Faster


Firefox may run quickly but it loads slowly; here's how to fix it.

(This tip is for experienced computer users only.)

You can slash Firefox's slow load time by compressing the DLLs and executables. There are many choices for compression but I suggest you use UPX which is free, efficient and time proven.


  1. Download UPX from
  2. Unzip upx.exe into your Firefox installation folder which is normally C:\Program Files\Mozilla Firefox.
  3. Make sure Firefox is not running then shell to a command prompt in the Firefox installation directory.
  4. Type in the following command in a single line and hit return:

    for %v in (*.exe *.dll components\*.dll plugins\*.dll) do upx "C:\Program Files\Mozilla Firefox\%v"

  5. If on some later occasion you want to unpack the files, just type in the command above but add the decompression switch "-d" after "do upx."


That's it; enjoy the difference!


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by steven 33 (not verified) on 17. May 2011 - 22:18  (72125)

I found some other ways to speed up firefox

by Blackbird on 24. February 2011 - 23:59  (67053)

If Firefox Is very... S-L-O-W... to load at start-up,....
PLEASE try this: (Non-Techie)
Very simple: If you do have several (or LOTS more...) Add-ons..., at the top of Firefox, Go to Tools > Options > Advanced Tab > Below Click on the "Update" tab > Under "Automatically Check for Updates to:" > UN-CHECK (Remove the Check mark) from "Add-ons". Hit "Okay" at the bottom. Now try re-starting Firefox.... I hope it starts up MUCH quicker for you now,....
HOWEVER..... You must now remember to occasionally do the following:
Go to: Tools > Add-ons > Select "Extensions" at the top > At the bottom-right, hit the "Find Updates" button.... Also, at the top of this window do the same for "Plugins". This is necessary since you have disabled the "Automatically Check for updates" of your "Add-ons".
(I found this "help" on a "Bing" search.)
This made Firefox load in less than 3 seconds,.... instead of MANY seconds..... I hope that this is HELPFUL to all who need it.

by anonymous1357854365346 (not verified) on 10. January 2011 - 5:50  (64198)

Not quite. What UPX does is compress exe files for fast startup, then decompress them afterward. In most cases this and the speedyfox is useless junk unless you have a ton of settings, addons, bookmarks, etc and your firefox is extremely slow to begin with. One way to keep down firefox startup times is to keep addons at a minimum and only have a couple bookmarks. I like to keep a text document with a bunch of bookmark links if I need them in the future... if you have tons of bookmarks. Another way is to buy more ram (or just buy a faster computer), and/or change ram cache setting in the about:config.

It's completely hit and miss, some .dll's will decompress faster than others, but on the whole and in my experience it's faster to just load the exe directly to memory instead of compress/decompress program files. This CAN BE extremely fast if you know what you're doing, and want to disable or change some .dlls. Otherwise I see no benefit to the average user. If you add a program to make another program faster, the end result is you're still using two programs instead of one ;)

If you want firefox to start faster on startup with an already fast computer or you don't care about boot up times, prefetch the executable file manually. Check your prefetch file for firefox and add it's corresponding .exe if it isn't there (yet), windows will add programs to your prefetch automatically or if prefetches have been deleted over a series of subsequent bootups. To give you an idea, this is similar to what the program "fasterfox" does with browser links. Fasterfox is another example of too much for too little, if you have a fast internet and a lot of ram, your internet isn't going to be faster prefetching every link on the page.

by Syamsul The Novice (not verified) on 23. August 2010 - 2:56  (56541)

This morning (Indonesia Western Time) I tried runing my FF-368 after selecting the 'compatibility' from 'default status' (= unchecked) to 'Windows 2000' as well as 'Windows 98/ME'. Both options don't work. FF even won't start.

by Syamsul The Novice (not verified) on 22. August 2010 - 16:49  (56526)

I have found it myself. Thank you anyway.

by Syamsul The Novice (not verified) on 22. August 2010 - 16:37  (56525)

Anonymous on Sun, 06/13/2010 - 18:01 wrote :
"Just go to properties and compatibility then press windows 2000".
Where can I find that 'Properties and Compatibility' stuff.

by Anonymous on 13. June 2010 - 18:01  (52031)

just go to properties and compatibility then press windows 2000

by Anonymous on 1. February 2010 - 0:36  (42506)

I tried the above steps (with the amended shell help from below.) Firefox takes just as long to open, but now nothing loads. After a couple more minutes, this error message appears: [Java Script Application] Error loading tz data version files! Status:0

I tried step 5 but the problem persists.

Any help is greatly appreciated.

by Anupam on 1. February 2010 - 4:36  (42522)

Please do not post the same comment repeatedly. You had posted this earlier too. If someone has a solution, they will post it.

by Anonymous on 1. February 2010 - 5:59  (42528)

Didn't mean to post it on that other person's post is all. Would have deleted it if I could have. Most sincere apologies.

by Anupam on 1. February 2010 - 6:10  (42530)

BTW, which version of Firefox are you having? I don't know if the above article applies to the newer versions of Firefox. If your problem does not go away, you should uninstall Firefox, and then reinstall it. Backup your extensions, themes, bookmarks, passwords before uninstalling with the FEBE add-on.

Firefox 3.6, which is the latest shows a little improvement in load up time, but not much.

by Anupam on 1. February 2010 - 6:05  (42529)

No problem :). Its just that some people make same repeated posts, and that becomes a problem. That's why we have to be watchful.

by Anonymous on 4. January 2010 - 22:03  (40265)

I have XP and Firefox took anywhere from 1-1.5 minutes to load. Added more ram and now it takes 15 seconds. Alot of things began to work faster.

by Anonymous on 20. November 2009 - 3:37  (36971)

This utility made my FF3 load really fast. Just run it periodically to clean up the SQLite database.

by Anonymous123 (not verified) on 28. September 2011 - 14:20  (80509)

I downloaded and ran speedyfox, and Foxfire starts and loads web pages faster than it ever has. thanks...

by MidnightCowboy on 14. December 2009 - 13:55  (38638)

Thanks for this which is already the subject of Gizmo's own article here:

by Anonymous on 7. September 2009 - 20:55  (32303)

Don't know how many people are still reading this topic by my solution was to run portable apps versions of both Firefox and Thunderbird on my hard drive. They load quickly by comparison.

by Anonymous on 21. August 2009 - 7:48  (31261)

what about us (lame) mac users?

by Anonymous on 9. June 2009 - 21:40  (23447)

This method never works for me. But fasterfox lite does work for me. It should be considered to change this review to at least add fasterfox lite.

by Anonymous on 2. June 2009 - 4:11  (22855)

Are you suggesting that the great firefox is..... slow!? Probably those 457 add ons needed to make it great.

by Anonymous on 18. September 2009 - 6:05  (32863)

i think this howto is suggesting it could be faster... perhaps you missed the howto on disabling ie.(that is to suggest ie sucks, sorry dude)

btw my firefox add-ons are adblock noscript autopager and forecastbar enhanced, these dont make firefox great, they make "the great firefox" work the way i choose.

by Anonymous on 26. June 2009 - 11:49  (24380)


by Anonymous on 1. June 2009 - 22:18  (22846)

An easier way to make firefox load faster-
Right click on your firefox icon and select the properties tab, where it says Compatability, check "Run this program in compatibility mode for" and select "Windows 2000" from the drop down menu.

Firefox loads faster on my laptop (Windows XP) after doing this, if it doesn't work for you, you can easily revert by unchecking "Run this program in compatiblity mode for" and try the way on this page. It's worth it to try this way first because I don't think it would have any side effects this way. This way might be just as good as the way on this page so try this easy trick first.

by Alex Robertson (not verified) on 28. August 2010 - 1:57  (56864)

Thanks so much. Loading time now at least 10 times faster.


by Anonymous on 15. December 2009 - 16:58  (38739)

Wow!! Thanks....MUCH better!!!

by Anonymous on 14. December 2009 - 11:21  (38627)

You are a genius!!!!!!!!

by Anonymous on 2. August 2009 - 18:24  (26149)

Worked for me. Good job.

by Anonymous on 15. July 2009 - 23:42  (25164)

I can't believe what a difference this has made. Thank you so much for this great bit of advice.

by Anonymous on 13. June 2009 - 0:26  (23736)

Works for me!!!!!!!!!!!!!!!!!

by Anonymous on 21. April 2009 - 14:07  (20240)

hi , Firefox is 1 to 2 second faster but chk out its memory usage...
for a blank window.. normally firefox takes about 33,000 k

but after upx ing the exe s and dll it increased to 49,000k starup (atleast)
and it reached upto 96,000k after 5 mins....

i am usin vista ultimate, amd 64 x2

so i guess this is not a good choice.