Microsoft claims that out of all most popular browsers, Internet Explorer 9 delivers the best energy efficiency. You can read their piece at MSDN.
Power consumption is an important consideration in building a modern browser and one objective of Internet Explorer 9 is to responsibly lead the industry in power requirements. The more efficiently a browser uses power the longer the battery will last in a mobile device, the lower the electricity costs, and the smaller the environment impact. While power might seem like a minor concern, with nearly two billion people now using the Internet the worldwide implications of browser power consumption are significant.
This post looks at how we measure power consumption, shares the results from recent engineering tests comparing browser power requirements, and explains how fully hardware accelerating Internet Explorer 9 has improved overall power efficiency.