Without repeating what has already been said, the patch basically preloads a library which can reduce the load time of the browser by up to 50%.

The developer of the patch yesterday complained about how the Windows operating system was making it nearly impossible for Firefox to utilize the faster startup time. He noticed that Windows Prefetch was the culprit. Turned on, it would render the improvements useless especially on slower machines that would otherwise benefit the most from them.

The developer has two suggestions on how to cope with the situation. First to disable prefetch (or the prefetch entry of Firefox) which may not make sense on all machines (SSD users on the other hand should disable prefetch). Second to install Firefox anew and reboot the system before starting the browser for the first time.

Above helps populate the Windows Prefetch in a less counter-productive way. Explanation: on warm startup Windows Prefetch records irrelevant IO operations and blocks Firefox startup to preload files that Firefox accesses after startup.

About 25% of all Windows users who have enabled telemetry data have Windows Prefetch turned off. The remaining 75% therefor may not benefit from faster Firefox 7 startup times because of those issues.

It is clear on the other hand that the majority of Firefox users are using the latest stable build, which is Firefox 6 at the time of writing. Those users won’t benefit from the faster startup times until Firefox 7 final is released. According to schedule, this is going to happen on September 27.

The best option then is to install Firefox 7 directly, and not use the internal updating mechanism to upgrade the browser. That is, unless Prefetch is disabled or another operating system is used.

You can read the complete blog post over at the Mozilla website.

The basic idea was to inform users and developers alike about the top add-ons that slow down the start-up of the
Firefox web browser. Slow Performance data has been added to the Mozilla Firefox Add-on Gallery.

The biggest offenders back then slowed down the browser by 74%. A Firefox user who’d install the top 5 add-ons of the list would slow down the start of Firefox by almost 300%.

The situation looks as grim one month later. The top five add-ons now slow down the browser by more than 350%. Some add-ons that have been previously on the list are not found in the top 10 anymore, but most add-ons that have been in the top 10 back then are still there, many with slower start-up times than before.

Mozilla has modified the top listing slightly. Only a top 9 list is displayed on the Slow Performing Add-ons page on Mozilla. Back then it was possible to load a top 50 list, which does not appear to be possible anymore.

Operating system filters have been added to the page which have not been there before, making it now possible to display the slowest add-ons for Fedora, Mac OS X, Windows 7 or Windows XP instead of a mixed listing.

If you look at those listings you will notice that only the add-ons of the top 9 listing are displayed. The start-up performance on the other hand differs widely. The worst offenders of all lists are SimilarWeb and Personas Plus under Windows 7. They slow down the startup time of Firefox by 223% and 202%. Compare that to the 25% or less add-on start-up time on the tested other operating systems. These numbers may be flawed, and it is very likely that they are considering the huge difference between Windows 7 and all other tested operating systems. While a flawed test is the most likely explanation, it could on the other hand be an extension specific problem instead. Only re-tests will tell.

The integration proofed to be more difficulty than anticipated which is why the patch has not been yet integrated into Firefox 4. The developer however has created a test extension that promises faster speeds for Windows Vista and Windows 7 users. Windows XP has been left out because the developer was not able to test the code under the operating system.

The restartless add-on places a new shortcut on the Windows desktop that loads the Firefox web browser. What does it do exactly? Start Faster “bypasses the Windows prefetch feature to start Firefox faster”, which means that it has been largely created for users who run Firefox from conventional platter-driven hard drives. Solid State Drive users on the other hand should, and usually have, prefetching disabled as it does not provide a speed increase anymore.

The developer notes that starting Firefox regularly with the extension installed will slow down the startup. This behavior will be fixed in the future.

The add-on for now has been published to demonstrate the feature, and get user feedback. It is likely that the feature will be integrated if user feedback is largely positive.

Firefox users on Windows who experience slow browser starts may want to give the extension a try to see if it speeds up the loading of the browser.

Please note that the extension adds a Windows service called Firefox Service which is set to start automatically. The intention of the developer is to integrate the service into Firefox which would then “handle Firefox updates” and “useful things” like deleting “prefetch files” or defragmenting “Firefox databases”.

Removal of the add-on in Firefox will not remove the service from Windows Services. That’s a serious flaw. To make matters worse, the service cannot be removed with the “sc delete” command. You can however delete it right in the Windows Registry. Here is how you do that:

Press Windows-R, type regedit and hit enter. Accept the UAC prompt if it appears. Navigate to the key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services, find the Firefox Service in the list, select it with the left mouse button and press delete on the keyboard.

Mozilla is not the first company to utilizes services in Windows; The installation of the Google Chrome browser adds the Google Update Service automatically to keep the browser up to date.

Firefox users that use the Windows operating system can install the Start Faster add-on directly at the Mozilla Firefox add-on repository. Additional information are provided at the developer’s blog.

Update: The test add-on has been removed. It is likely that the technology will be implemented into future versions of the browser.

That however appears to be a thing of the past, at least if the proposed patch passes quality control. Chances are however good that it will be compiled in one of the latest nightly versions of Firefox 4 Beta. Here is what Taras Glek, the developer who proposed the code change, discovered:

We page in most of xul.dll and mozjs.dll. So i figured why not try lazy-linking libxul and preloading it. Turned out lazylinking didnt make any difference, but
preloading seems to consistently shave up 2seconds of startup on my profile(40%).
I’m going to doublecheck on my favourite user’s slow computer. Here is the patch in meantime.

Basic idea is that the sequential flag + bullshit read tricks windows into reading xul in 2mb chunks instead of stupid 32k(or smaller) ones. Have to do it this way because there is no fadvise() on Windows(that I know of) A big sequential read cuts down on a lot of seeks.
[..]

I just confirmed, this also works wonders on slow harddrives. Shaved around 50% off cold startup on my reference slow system

A loading time reduction of 40-50% with a 20 line patch, that sounds efficient. But how is this achieved? From what I can gather, the developers are now pre-loading files in larger chunks which cuts down on the loading time of the browser.

It will be interesting to test this on computers with slow Firefox startup times. Information about the patch are posted on Bugzilla. (via)

There are a few things that Firefox users can to do make Firefox start faster. There is the Firefox preloader application that loads on system start, the Firefox extension Bar Tab which loads tabs on demand and not all together on startup, cleaning the Firefox preferences file, the SpeedyFox software for Windows, or Vacuum Places add-on to optimize the SQLite databases used by the browser.

Long time Ghacks reader OAlexander just emailed me another tip to make Firefox start faster that I have not heard about before. He mentioned that he removed excess locales from his installed extensions and noticed that Firefox would start up noticeable faster.

Firefox extensions often come with multiple locales to provide users from all over the world with information in their own language. Most users usually only need one or maybe two of the locales. It appears however that all locales are loaded on startup when the extension is loaded (Can anyone confirm this?)

So, to make Firefox start up faster users would have to delete excess locales from the Firefox extensions. An unzip software like 7-Zip is required for that operation. I explain how it is done with 7-Zip.

Make Firefox Start Faster

The first task is to locate the Firefox profile directory, which is the directory where the extensions are stored in. Firefox 3.6 and up users can click on Help > Troubleshoot Information to launch the file browser of the system with the profile folder as the selected folder.

Before we start modifying anything we need to backup the extensions folder. This is just a precaution, but it is always better to have an option to restore a previous state.

Open the extensions folder and take a look around. Some extensions are stored in folders, while others are stored in .xpi files. The folders are basically unzipped xpi files, so no need to worry about the differences.

What you need to do now is to fire up your unzip software and navigate to the Firefox profile folder. 7-Zip users can copy the file path from the system file browser and paste it into the path field in 7-zip. Make sure you close Firefox at this point, otherwise you will not be able to remove content from the extensions since they are in use when Firefox is open.

I suggest to work your way from top to bottom, starting with the xpi files and not the folders. Simple double-click on an xpi file to open its contents in 7-Zip. You will notice that they have a similar structure as those folders in the extensions root folder.

The path to the locales is always the same: Extension root folder > chrome > locale > filename.jar

Follow the path. Once the local folder is the root folder you may notice that multiple locales are provided by the Firefox add-on. You may now select all but the locales that you want to use. Press delete afterwards to delete them from the extension. Confirm that you want to delete the folders and files.

Now switch back to the extensions directory and repeat the process for all installed extensions. The folders are handled the same way.

Once all locale folders that are not needed have been removed it is time to start Firefox to see if the modification has made a difference. The effect depends largely on the installed extensions. Users with dozens of extensions may see a big decrease in startup time.

There is one problem though that needs to be mentioned. It is likely that extension updates will add the locale folders again to the extension. Which means that Firefox users need to delete the locale folders again whenever an extension gets updated.

Did you try this tip? What was the result on your system? Have another tip to speed up Firefox? Let everyone know in the comments.

Far more interesting than this well known feature is another option that is quite hidden in the same menu. Let me first explain how you open it. The Firefox options open in a new window and are located in the Tools > Options menu. The Main tab of those options define the Startup options which includes setting the homepage.

It is furthermore possible to configure Firefox to open the tabs and windows from the last Firefox session.

As you can see that option can be configured in the same menu. It does come in handy if you regularly continue your work from the last session and do not want to open the websites over and over again. I think that’s a pretty interesting option that gets overlooked quite often.