Google's new Chrome 3.0 is the fastest of the top five Windows browsers, and beats every rival, including Apple's Safari, by comfortable margins, benchmark tests show.

Both Chrome and Safari use the open-source WebKit browser engine.

According to tests run by Computerworld , Chrome 3.0, which Google launched last week, is the fastest production version of the top five Windows browsers. Chrome renders JavaScript more than nine times faster than Microsoft's Internet Explorer 8 (IE8), is over five times faster than Opera Software's Opera 10, two-and-a-half times faster than Firefox 3.5 and 30% faster than Safari 4.0.

Last week, Chrome's engineering director boasted of his browser's speed , claiming that the 3.0 update was 25% faster at rendering JavaScript than its predecessor, Chrome 2.0, and 150% faster than the original version, which debuted in September 2008.

Computerworld ran the SunSpider JavaScript benchmark suite in Windows XP Service Pack 3 (SP3) three times for each browser and then averaged the scores.

Most browser makers have been aggressively promoting improved JavaScript performance for over a year now, when Mozilla began touting the performance boost its new TraceMonkey JavaScript engine gave to what eventually was tagged as Firefox 3.5

Only Microsoft has disparaged such benchmarks, calling them nothing more than a "browser drag race" that doesn't accurately portray real-world use. Instead, Microsoft has used download tests of the 25 most popular Web destinations to claim IE8 is actually faster than Firefox or Chrome where it counts.

Although Chrome is the fastest browser for Windows, its usage share last month was just 3% , a small fraction of the 67% held by all versions of IE. Firefox, Safari and Opera, meanwhile, accounted for 23%, 4% and 2%, respectively, according to Net Applications' August data.

Google has yet to ship stable versions of Chrome for Mac and Linux . The Mac version -- the latest is 4.0.211.2 -- has remained in Google's "dev" channel since June, indicating its not yet ready for official beta testing.

Chrome 3.0 for Windows can be downloaded from Google's Web site.