Microsoft on Tuesday issued a seventh developer-oriented platform preview for Internet Explorer (IE) 9, its next web browser, the second such preview since a public beta release in September. The IE 9 platform previews aren't particularly interesting to end users, but each has offered impressive underlying enhancements, and this one is perhaps the most impressive yet: According to Microsoft, changes to IE 9's JavaScript engine result in this browser now being the fastest on Earth.

Before anyone breaks out the champagne, however, Microsoft is also warning users that the JavaScript performance tests so beloved by its competitors are, in fact, quite misleading—a charge I've made myself in the past. Microsoft's normal focus on real-world browser performance is, I think, a far more compelling story.

"We think people should evaluate browser performance with real-world scenarios," Microsoft Vice President Dean Hachamovitch wrote in a blog post announcing the new preview. "Real-world scenarios involve using all the subsystems in the browser together rather than looking at single subsystems in isolation. Using a narrow slice of features to assess the big picture makes as little sense here as using the Acid test to understand standards compliance." (He's right about the Acid test, as well, which was written as much to discredit Microsoft as it was to prove any form of HTML 5 compliance; that said, IE 9 also scores impressively on this test.)

OK, but in this latest platform-preview guise, it turns out that IE 9 does, in fact, score higher on the industry's "SunSpider" JavaScript test than any other browser, including those browsers—Firefox, Chrome, and Safari—whose makers seem particularly fixated on such numbers. In fact, Mozilla is already disputing IE 9's latest results, though the complaint seems somewhat specious.

No matter. As Microsoft is finally publicly stating, these tests are all completely bogus and not indicative of real-world performance. Fortunately, the software giant has put a lot of effort into promoting this aspect of the browser, as well, and while the company has nicely kicked up a hornet's nest with this overdue commentary on the state of baloney in the browser market, the really interesting bit will come when the final version of IE 9 arrives and can compete with then-shipping browsers from other makers.

If you're interested in checking out the latest IE 9 platform preview, and viewing Microsoft's new performance tests for yourself, please do visit the IE 9 Test Drive website.