February 26, 2008 2:53 PM PST

New MacBook Pro takes a dive on battery life? Well, no

Posted by Dan Ackerman

(Credit: Apple)

Some conflicting accounts coming out of the Web-o-sphere on Tuesday about Apple's revamped MacBook Pro laptops. At the heart of the controversy are reports that the new 15- and 17-inch Pro models have taken a nosedive on battery life, despite the inclusion of allegedly power-saving Intel Penryn processors.

Both Ars Technica and Gizmodo pointed out that Apple's own numbers on how long the battery should last in a 17-inch MacBook Pro have changed with the new models--going from more than 5 hours to only 4.5 hours.

There are actually a couple of different things going on here, all of which add up to new MacBooks that should last just as long as their predecessors, if not a little longer.

Apple says it's changed the way it reports battery life. It used to report numbers from three stock battery life tests, a so-called "highway" test, designed for maximum battery life, a DVD playback test (similar to what CNET uses), and a wireless productivity test.

Apple's Anuj Nayar tells us that the company used to publish all three scores on its site, but highlighted the highway test. Now, the highway test and DVD playback tests are out, and the wireless productivity test is the new default. So looking at Apple's older numbers is a bit like comparing you-know-what to oranges.

On the other hand, the new Penryn processors and optional LED backlit display (17-inch Pro only) should offer some advantages in battery life.

Battery numbers should always be taken with a fairly hefty grain of salt--your laptop's battery life is highly dependent on how you use it, from applications to screen brightness to USB-powered peripherals. We'll know more when we get our hands on one of these new models and run it through our own testing, so stay tuned.