The Sunspider results have become a familiar metric in how fast browsers are judged to be, and Microsoft's IE8 was judged harshly for its poor performance.
At the preview event for IE9 at MIX, Microsoft's Principal Program Lead Jason Weber insisted that the latest version of Internet Explorer would 'change the way you think' with its speed.
And yet, Microsoft's own published results confirm that the latest build of Apple's Safari browser, Opera and Google's Chrome are all still faster.
Weber justifies the difference between its 604 score and Opera 10.50's 287 as "less than one eye blink", pointing out that major changes under the bonnet of Internet Explorer will have a great impact on web browsing.
"We're speeding up the real Web today," says Webber; "we believe we've sped up everything by 10 or 11 per cent".
In truth, the results do show a massive performance boost for Internet Explorer, and push it past the popular Mozilla Firefox browser.
The real world difference between the main browsers are now negligible - fractions of a second and unlikely to affect user experience or even be noticeable to the vast majority.
Microsoft will feel that in keeping up with the Joneses, it makes the speed race less important and allows more focus on IE's security, privacy and other enhancements to real-world browsing.
But, with Apple and Google both working on their next generation browsers, questions are likely to be raised over how fast IE9 will be in comparison to its rivals when it finally becomes available to the public.