Mozilla’s latest Firefox 4 browser is sweepingly outpacing Microsoft Internet Explorer 9 even though there is still time before the open source company will introduce an automatic update to its aging Firefox 3.5 browser. Mozilla's Asa Dotzler reported that early this month Firefox 4's usage began to show a sharp increase while IE9 continued on a much more gradual climb.

"Since activating the Firefox Update system and alerting Firefox 3.5 and 3.6 users to the availability of Firefox 4, the line has really picked up some speed," Dotzler wrote in a blog post with an accompanying graph.

"Internet Explorer 9's trajectory looks very similar to what we saw with IE8 and IE7 before it," he added. "Microsoft pushes new versions at an excruciatingly slow pace."

StatCounter data cited by Dotzler shows that Firefox 4 made up about 16% of the browser market Monday while IE9 is coming only to 5%.

"IE9's steady progress should put it around 10 percent in a couple of months," he predicted.

Earlier Mozilla announced its plans to introduce an automatic update of its Firefox 3.5 to the latest version and at the very least to the 3.6. The move is expected to bring additional 12 million users of Firefox 4.