By Sam Oliver

Published: 08:35 AM EST

Apple said Friday that more than 11 million copies of its new Safari 4 web browser have been downloaded in the first three days of its release, including more than six million downloads by users of Microsoft's Windows operating systems.

Introduced Monday following a multi-month public beta test, Apple bills Safari 4 as "the world's fastest, most innovative browser," saying its new Nitro JavaScript engine that executes JavaScript nearly eight times faster than IE 8 and more than four times faster than Firefox 3. The Cupertino, Calif-based company's test also show it to load HTML web pages more than three times faster than IE 8 and three times faster than Firefox 3.

"Safari 4 is an incredible success on Mac and Windows with more than 11 million downloads in the first three days," said Philip Schiller, Apple's senior vice president of Worldwide Product Marketing. "Safari users love the incredible speed and innovative features like Top Sites, Full History Search and Cover Flow."

Safari 4 includes HTML 5 support for offline technologies and showcases support for advanced CSS Effects, enabling an entirely new class of web applications that feature rich media, graphics and fonts. The Apple browser is also the first browser to pass the Web Standards Project's Acid3 test, which examines how well a browser adheres to CSS, JavaScript, XML and SVG standards that are specifically designed for dynamic web applications.

With the release of Mac OS X 10.6 Snow Leopard this September, Safari will run as a 64-bit application, boosting the performance of the Nitro JavaScript engine by up to 50 percent, Apple claims.

The new operating system will also make Safari more resistant to crashes by running plug-ins in a separate process, so even if a plug-in crashes, the browser continues to run and the user simply has to reload the affected page. Safari running on Snow Leopard also delivers HTTP streaming, making it easy to deliver high-quality audio and video in industry standard formats from any web server without the need for browser plug-ins.

Safari 4 is available for both Mac OS X and Windows as a free download at Apple's Safari website.