Browser faceoff: IE vs Firefox vs Opera vs Safari

Web 2.0, with its complex sites and rich Ajax applications, is an increasingly demanding platform for a browser. In this review feature, we look at how the leading browsers measure up.

When Tim Berners-Lee presented his employer CERN with the first browser, World Wide Web, to facilitate information flow between the different departments in the European nuclear research centre in Geneva, he little suspected that it would cause a revolution in the information age. Today, the browser is probably the most widely used computer application.

However, the tasks performed by a web browser have changed significantly. As well as displaying text and images, the modern browser needs to accommodate technologies such as JavaScript, DOM and XML in Ajax-based programs. Even if you're not familiar with Ajax, you'll probably have used it via Google Maps, Google Mail or AjaxWrite; sites such as Flickr and Last.fm also make intense use of this technology. Ajax has even taken root in the business environment: for example, 24SevenOffice is an Enterprise Resource Planning (ERP) and Customer Relationship Management (CRM) solution that runs in a web browser. The advantage of this Web 2.0 technology is platform independence: you don't need a specific operating system or processor to run Ajax applications — just a compatible browser.

Web 2.0 applications and sites place the focus firmly on browser performance. Anyone who still believes that the speed of your DSL connection is the only potential bottleneck is gravely mistaken. Key parts of Ajax applications run locally, which means that — all other things being equal — the speed of the browser will be crucial in determining the user experience. For Ajax-based business applications, the browser becomes even more important because data will be accessed from within-firewall servers rather than the internet. Companies deploying such solutions will be able to improve employee productivity by paying attention to browser performance.

To test the performance of browsers when handling Web 2.0 technologies, we used the iBench 5.0 test suite and SunSpider, a Javascript benchmark.

iBench evaluates browser performance by measuring how fast HTML, XML and JavaScript is handled. The web pages are held on a local web server. SunSpider, which (unlike iBench) is available online, concentrates solely on JavaScript performance. Tests are grouped into nine categories, including 3D, bit operations, cryptography and string processing; there are several tests within each group. The benchmark runs each test multiple times and calculates an error range.

Obviously the speed of the hardware platform is a crucial variable. In our browser tests under Windows Vista and Mac OS 10.5.2 Leopard, we used the following components:

The seven browsers we tested load HTML and XML/CSS pages under Windows Vista at a variety of speeds. According to iBench 5.0, Safari 3.1 is the fastest browser and Opera 9.27 the slowest; the latter takes over twice as long as any other browser to load HTML pages. However, the beta version of Opera 9.5 performs significantly better, and is on a par with the middle-ranking browsers.

In the iBench 5.0 JavaScript tests, Safari 3.1 is again the fastest browser, while Microsoft's browsers bring up the rear in JavaScript/HTML DOM tests. The JavaScript tests also expose greater performance differences among the browsers than the HTML/XML tests: in the JavaScript tests, the slowest browser is about 10 times slower than the fastest.

The various beta versions show significant performance improvements in some tests. For example, Firefox 2.0.13 completed the JavaScript/HTML DOM test in 3.1 seconds, while the Firefox 3 Beta 5 took only 0.65 seconds. The two Opera browsers show a similar pattern: Opera 9.27 was slowest in the JavaScript test (2.54s), while Opera 9.5 Beta 4758 delivered the second best result (0.36s).

It should be noted that iBench 5.0's reported values for the Safari browser are underestimates of the actual timings, which we checked manually. The reason is the measuring methodology in iBench 5.0, which uses the 'onload' event to signal that a page has been loaded: most browsers load the page, decode images and run stylesheets and scripts before firing 'onload'. Safari does not do this. There's no doubt that Apple's browser is fast, but it's not as far ahead of its competitors as iBench 5.0 suggests — as our next test shows.

Timings in seconds: shorter bars are better.