Internet Explorer isn't the fastest or most featured-packed browser around, but it might be the most power efficient. Hoping to determine which software would give his aging desktop replacement the longest battery life, Ciprian Adrian Rusen put IE9, IE10, Chrome 18, Firefox 11 and Opera 11.62 to the test, and both of Microsoft's offerings had a clear edge on competitors.
Internet Explorer trumps Chrome, Firefox, Opera in battery test - TechSpot News