Seeing as most of the time spent on a laptop is spent online, AnandTech ran exhuastive tests on Windows machines, Intel and AMD, netbook and notebook, to see if switching browsers makes any difference in battery life. And hey, it does! In some tests, there was a 30% advantage between the worst browser—always Safari—and the best—Internet Explorer 8. Seriously.

In fact, Microsoft's browser came in front across the board, even inching out Firefox with Adblock by a few percent. It's hard to say why IE8 is so power-thrifty, but the most processor-intensive operations a browser does outside of running Flash content are in rendering Javascript, which IE8 kind of sucks at. So, mystery solved, maybe! Firefox, Chrome and to a lesser extent Opera held up fine, but depending on what kind of laptop you're running, and how willing you are to ditch your browser, there are quite a few sweet battery minutes up for grabs here. Full breakdown at [AnandTech]

AMD, as part of a some kind of PR campaign, is saying the culprit is a battery testing suite called MobileMark 2007:

the parameters for this test include having the screen at just 20 percent brightness, Wi-Fi turned off and no music, video, games or Web pages running. More or less, the test turns a computer into a dimly lit clock, then sees how long it can run.

That is exactly the kind of test you'd have to run to hit manufacturers' 50-100%-inflated figures, and the perceived ubiquity of the test gives it an air of authority—or at least respectability—within the industry. Using anything more honest would put a manufacturer at a competitive disadvantage.

This is where the story lapses into accusations of subterfuge: AMD says these tests don't just benefit laptop manufacturers in general—they're unfairly biased towards Intel, whose chips are optimized for these less-than-realistic scenarios. It's easy to see how this would be upsetting, but it's not clear what AMD can really do. They're proposing a system by which manufacturers show two battery ratings—one the shows a theoretical, low-use maximum, and one that reflects heavy use. (To their credit, Sony already does something like that). Intel tacitly admits the practice, but is predictably standoffish about it, while AMD doesn't inspire much confidence:

By 2010 or 2011, something might show up from a consortium that could be used. It takes two to three years."

Well, thanks for trying, I guess! [NYT]