Tiny patch cuts Firefox 4's startup time in half

A 20-line coding fix boosts the Web browser’s speed on Windows, particularly for slower systems.

While all the world scrutinized the proposed "Do Not Track" feature for Mozilla's Firefox 4 on Monday, a tiny patch quietly emerged that promises to cut the open source browser's startup time in half on Windows.

The 20-line patch works by preloading Firefox's XML Markup Language (XUL) library. Whereas previously that library was loaded in chunks of 32KB or less, the patch works by "tricking" Windows into preloading the library in 2MB increments instead, Mozilla developer Taras Glek explained recently on Mozilla's Bugzilla forum.

The patch shaved two seconds off of the browser's startup time in Glek's initial trial -- representing a performance improvement of 40 per cent -- but the results were even better on a machine with a slow hard drive.

"Shaved around 50 per cent off cold startup on my reference slow system," he wrote. "This patch works better than I expected. Not only does it trade random xul.dll io for faster sequential io. It also reduces the amount of seeks later on (ie no need to seek for xul bits), which significantly speeds up io on other files."

The Need for Speed

In Firefox's competition with Google's Chrome and Microsoft's Internet Explorer browsers, speed has become a pivotal factor.

Chrome is often viewed as the leader in that respect, but Firefox 4 promises significant improvements, not just through this latest patch but also via the inclusion of the new JägerMonkey JavaScript engine.

With 23 per cent of the browser market in December, Firefox holds the No. 2 position in that arena, following only Internet Explorer, which accounts for 57 per cent, according to the latest data from researcher Net Applications.

While Microsoft's share last month represented a decline from the 58 per cent it held in November, Firefox enjoyed a small increase over the 23 per cent it held in November, Net Applications reported. Firefox was also recently named the No. 1 browser in Europe by research firm StatCounter.

Coming Soon?

Slated to appear soon in a Firefox 4 nightly build, the feature could ultimately make its way into the browser's next official version, which is due next month. If that happens, it could give Firefox another boost ahead of the competition.

Follow Katherine Noyes on Twitter: @Noyesk.

Join the Good Gear Guide newsletter!

Error: Please check your email address.

Tags open sourceInternet-based applications and servicesFirefoxWeb-based Applicationsapplicationsbrowserssoftwareinternetmozilla

Our Back to Business guide highlights the best products for you to boost your productivity at home, on the road, at the office, or in the classroom.

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Katherine Noyes

PC World (US online)
Show Comments

Essentials

Microsoft L5V-00027 Sculpt Ergonomic Keyboard Desktop

Learn more >

Lexar® JumpDrive® S57 USB 3.0 flash drive

Learn more >

Mobile

Lexar® JumpDrive® S45 USB 3.0 flash drive 

Learn more >

Exec

Audio-Technica ATH-ANC70 Noise Cancelling Headphones

Learn more >

HD Pan/Tilt Wi-Fi Camera with Night Vision NC450

Learn more >

Lexar® Professional 1800x microSDHC™/microSDXC™ UHS-II cards 

Learn more >

Lexar® JumpDrive® C20c USB Type-C flash drive 

Learn more >

Budget

Back To Business Guide

Click for more ›

Most Popular Reviews

Latest News Articles

Resources

PCW Evaluation Team

Azadeh Williams

HP OfficeJet Pro 8730

A smarter way to print for busy small business owners, combining speedy printing with scanning and copying, making it easier to produce high quality documents and images at a touch of a button.

Andrew Grant

HP OfficeJet Pro 8730

I've had a multifunction printer in the office going on 10 years now. It was a neat bit of kit back in the day -- print, copy, scan, fax -- when printing over WiFi felt a bit like magic. It’s seen better days though and an upgrade’s well overdue. This HP OfficeJet Pro 8730 looks like it ticks all the same boxes: print, copy, scan, and fax. (Really? Does anyone fax anything any more? I guess it's good to know the facility’s there, just in case.) Printing over WiFi is more-or- less standard these days.

Ed Dawson

HP OfficeJet Pro 8730

As a freelance writer who is always on the go, I like my technology to be both efficient and effective so I can do my job well. The HP OfficeJet Pro 8730 Inkjet Printer ticks all the boxes in terms of form factor, performance and user interface.

Michael Hargreaves

Windows 10 for Business / Dell XPS 13

I’d happily recommend this touchscreen laptop and Windows 10 as a great way to get serious work done at a desk or on the road.

Aysha Strobbe

Windows 10 / HP Spectre x360

Ultimately, I think the Windows 10 environment is excellent for me as it caters for so many different uses. The inclusion of the Xbox app is also great for when you need some downtime too!

Mark Escubio

Windows 10 / Lenovo Yoga 910

For me, the Xbox Play Anywhere is a great new feature as it allows you to play your current Xbox games with higher resolutions and better graphics without forking out extra cash for another copy. Although available titles are still scarce, but I’m sure it will grow in time.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?