When Steve Jobs announced that the MacBook Air would have a 5 hour battery life, I laughed. Short of Apple sticking a hydrogen fuel cell in the Air there was simply no way you were going to get 5 hours out of this thing under any sort of heavy usage. What shocked me even more is how few questioned the 5 hour figure. Have we all forgotten about optimistic battery life ratings? I like to give Apple the benefit of the doubt and not call out RDF whenever a new product with exciting features launches but seriously folks - 5 hours?

We're still hard at work on the MacBook Air review, but this data was too important not to share right away. By now you've heard that under "normal" usage, the Air can only manage about 2.5 hours of battery life. That's true and at the same time it isn't. I touch on part of this in the review, but the MacBook Air isn't designed to be your work notebook - no ultra portable is. It's a notebook for a writer, for someone taking notes in class; it's a second notebook, or a third system. As such, the typical usage model can be very different than your standard notebook.

At the same time, most of the people considering the Air aren't looking at it as a second notebook or a third system, they are looking at it as their primary notebook (and will be left sorely disappointed or frustrated after a while). The end result is that you need a handful of battery life tests to really cover all bases. And that's what I've done.

I scripted together three tests: wireless web browsing, DVD playback and a multitasking workload.

The wireless web browsing test uses the 802.11n connection to browse a series of 20 web pages varying in size, spending 20 seconds on each page (I timed how long it takes me to read a page on Digg and came up with 36 seconds; I standardized on 20 seconds for the test to make things a little more stressful). The test continues to loop all while playing MP3s in iTunes. This test is designed to simulate the intended usage of the MacBook Air: something you can carry around with you to class, work, on the train, etc... to comfortably and quickly browse the web, take notes and generally be productive all while listening to music. It's like a big iPhone...without the phone part.

Despite the lack of an internal optical drive (I've never been so tempted to use the f-bomb in a review before), the MacBook Air will play DVDs. You just kind of need to have them on your hard drive and I'll just assume you have the original disc safe at home. This test is simple: I play Blood Diamondin a loop until the battery runs out.

The final test is the multitasking workload, and this test isn't really that intensive for a normal system but thanks to the terribly slow iPod hard drive in the Air - it's quite stressful. For this benchmark I'm downloading 10GB worth of files from the net (constant writes to the drive), browsing the web (same test as the first one) and watching the first two episodes of Firefly encoded in a 480p XviD format (Quicktime is set to loop the content until the system dies). There's nothing too extreme about this workload, I could definitely come up with worse - but this would be light to moderate usage on a MacBook or a MacBook Pro, and it'll show how the Air stacks up.

The system was set to never shut off the display and never go to sleep, although the hard drive was allowed to spin down when possible. The display brightness was set at 9 blocks (just over 50%), which I felt was comfortable for both day and night viewing. The system itself was a standard MacBook Air with an upgrade to a 1.8GHz processor, but used the regular PATA hard drive - not the SSD (I'll touch on SSD performance once I get my drive).

Ready for the results?

Apple's 5 hour claim is laughable but not as much as I expected. If I wanted to I suspect I could hit 5 hours by making the web browsing test less stressful, but my focus was on real world usage scenarios, not proving Apple correct. Regardless, 4 hours and 16 minutes doing what I consider to be the intended usage model of the Air is respectable. It's not great, but it's not terrible either.

The DVD playback test is also decent, you can watch a full length movie on the Air (even The Godfather). But watching two back-to-back isn't possible (although I do think you could squeeze two viewings of Rambo in there and frighten your fellow airline passengers).

And then we have the multitasking scenario. At just under two and a half hours, this isn't your do-everything notebook. That should've been obvious from the get-go with the whole lack of an optical drive, 2GB memory limit and no built-in Ethernet port.

I'll save more thoughts and discussion for the full review but this data was too important not to share.

On a side note, in doing the DVD playback testing on the MacBook Air I realized something I hadn't previously about Leopard. It looks like Apple finally fixed the horrible de-interlacing problems with its previous DVD player application. There are now actual de-interlacing controls and image quality seems vastly improved; I may have to run HQV to see what sort of improvement there is over Tiger. What took me so long to notice this about Leopard? Well it seems like Apple has finally fixed issues with DVD playback, just when everyone is starting to move to HD-DVD and Blu-ray. Great.

Be sure to read our other MacBook Air coverage:

Inside Apple's MacBook Air

The MacBook Air Ethernet Dongle: Performance Explored



View All Comments

  • AndyKH - Thursday, February 7, 2008 - link

    Conditioning is a thing of the past, it only applies to NiCd and NiMH, but not Lithium chemistries. Unfortunately many manufaturers of cell phones, laptops and consumer electronics haven't communicated that to their technical writers.
    One thing you have to do with lithium batteries is resetting the battery gauge once in a while, but it shouldn't be necessary just after purchase, as the battery should have the rated capacity unless it's been in storage for some time before being sold.
  • JarredWalton - Thursday, February 7, 2008 - link

    If by "conditioning" you mean running the battery dead and fully charging it... well, I can say for sure that at least two of the tests are done with a conditioned battery. :) Reply
  • darely0s - Thursday, February 7, 2008 - link

    The battery life actaully seems pretty decent for such a small battery. However, I believe most DVD movie playback battery tests involve playing the DVD from a built in optical drive and I'm guessing that power consumption of the optical drive will be a bit higher than a hard drive. Not to mention the fact that playing a DVD from an optical drive doesn't necessarily mean the hard drive can spin down or stay that way for the duration of the movie. The difference may only be a few minutes of battery life, but I think it would be helpful to perform a battery life test on a notebook with an optical drive using both methods (playback via DVD or from HD) Reply
  • Samus - Thursday, February 7, 2008 - link

    I agree. I'm sure the 1.8" iPod drive sucks far less power than any optical drive. Reply
  • soydios - Thursday, February 7, 2008 - link

    I have a Lenovo X61t, and I'm able to get the same battery life as in the Browsing&MP3 test with the 9-cell extended battery under Vista Business 32-bit, and my tablet can do a helluva lot more than the Air.
    Even though my X61t obviously doesn't have an optical drive either, I don't miss it. The only times I ever need to use an optical disc are when I'm at my desktop in my dorm room.
  • Samus - Thursday, February 7, 2008 - link

    Yay I love my X61. I get about 3 hours on the standard 6-cell battery of mixed use. If I'm just surfing the web it's a little more than 3 hours though.

    However, I've never been unable to finish a full DVD movie I ripped to the hard disk, including Zodiac which I just recently watched on it start to finish (2 hours 40 mins) on my last flight.
  • Verdant - Thursday, February 7, 2008 - link

    i get about 4.5 hours on mine, though it is the larger battery: that is with light wireless usage and the battery profile screen brightness is down two levels, sometimes i plug in a portable hd that is powered by usb power.

    with the base with the extra battery it does over 7 hours.

    What amazes me is the battery life when i use the optical drive, i would have thought it would dig deeper into the battery, but even with the dvd drive fairly active it lasts over 3 hours.
  • strafejumper - Thursday, February 7, 2008 - link

    i remember last time i saw a review of laptop battery life here on anandtech none of the $2000+ laptops could get through a whole dvd. Glad to see one that you can actually watch a 2 hr movie on. Reply
  • brianb - Friday, February 8, 2008 - link

    Sorry here's the exact link of the Air Migration post:

  • Pirks - Friday, February 8, 2008 - link

    Yeah, some braindead moron didn't realize that he can use high-speed transfer through USB instead of slow Wi-Fi. So what? How is this particular case of not working human brain related to Macbook Air? Reply

Log in

Don't have an account? Sign up now