Computerworld ran the SunSpider suite in Windows XP three times for each browser, then averaged the scores. In SunSpider, smaller numbers are better. The results were: Chrome 188.8.131.52 -- 1275; Firefox 3.0.5 -- 3037; Safari 3.2.1 -- 3050; Opera 9.63 -- 4139; and IE8 RC1 -- 5573.
Although IE8 RC1 was the slowest of the five browsers, its SunSpider score was approximately 70 percent faster than IE8 Beta 2's, which was released in August 2008, and tested by Computerworld last month.
Microsoft, however, continues to dismiss benchmarks like SunSpider. In an interview earlier this week when the company launched IE8 RC1, senior product manager James Pratt criticized such tests. He described them as "micro-benchmarks" that place an emphasis on scores as a "drag race" that Microsoft isn't about to enter.
"We're at the point, with what people do in the browser, that users can't really tell the difference between browser [performance]," he said. "Beyond building a performance lab, which we've done, it's very difficult to tell which browser is fastest. The reality is that for most users, they'll all be comparable."
Other browser builders would disagree.
Computerworld is an InfoWorld affiliate.