How Apple's new MacBook gets nearly as much battery life as the MacBook Pro with a battery half the

Posted:
in Current Mac Hardware edited April 2015
Apple has packed its all-new MacBook with some impressive technology, but its outstanding battery life -- nine hours from a single charge -- may be the most staggering. AppleInsider took a look under the hood to see how they could have done it.




On the surface, nine hours of battery life may not seem all that spectacular. The refreshed 13-inch MacBook Pro, which also runs on Intel's power-sipping Broadwell chips, got nearly two hours more during our testing earlier this month.

There's one catch: the MacBook Pro has a battery nearly twice the size.

The MacBook's 39.7 watt-hour (Wh) power reserve is 35Wh smaller than the 74.9Wh unit on the MacBook Pro. It's even smaller than the 54Wh part stuffed into the 13-inch MacBook Air, which itself lasts for 12 hours off the plug.

So how does Apple do it? The answer lies in a combination of new technologies: an updated Retina display, ultra-low-power RAM, and Intel's Broadwell processors.

Retina Redux

Though we haven't had a chance to test it yet, the 12-inch Retina display is almost certainly the new MacBook's biggest power draw. High-resolution displays are inherently power hungry; in addition to the graphics processing power required to drive millions of pixels, those pixels are very densely packed, making it more difficult for the backlight to push its way through.

Generally, this mandates a larger battery to drive a more powerful backlight -- we saw that in action with the third-generation iPad and second-generation iPad mini, which found themselves fattened up to support their new Retina displays.

In TFT-LCD displays, some portion of each individual pixel is covered by transistors that control the behavior of the red, green, and blue subpixels. Depending on the panel type and design, the uncovered portion -- or the "aperture" -- can be as little as half of the pixel.

As the aperture gets smaller, the backlight needs to be more powerful to reach the same level of display brightness, driving up power requirements. Fortunately, there are a number of ways to make the aperture larger.


One method is to change the materials that the transistors are made of. LTPS-based panels, like those found on Apple's latest iPhones, boast higher electron mobility which allows the transistor to be smaller, thus increasing the pixel aperture.

Another option is to redesign the pixel itself, which is an approach that Apple seems to have taken with the new MacBook. The company doesn't specify exactly what they've done, but a small animation on the MacBook landing page shows some components being layered on top of others, expanding the aperture.

While we don't know which parts are being depicted, Apple has explored stacking various pixel components in the past. In a patent awarded to Apple in January, inventors Youngbae Park, Shih Chang Chang, Vasudha Gupta, and John Z. Zhong discuss splitting the gate or data lines in half, then stacking the two halves on top of each other.

Regardless of the practical implementation, Apple says that their larger aperture ratio enabled them to fit a backlight that's 30 percent more efficient than the backlight in its other notebooks. This is a significant improvement on its own, and substantially eases the display's power requirements.

Broadwell Core-M

After the display, the processor most directly affects device battery life. For the MacBook, Apple chose Intel's Broadwell Core M line of ultra-low voltage dual-core chips.

As the 'tick' in Intel's processor cycle, Broadwell brings minor architectural changes, but its primary claim to fame is a process shrink from 22 to 14 nanometers. Broadly speaking, a process shrink means making transistors smaller, which allows chipmakers to pack more transistors into the same space, increasing efficiency.

Intel says Broadwell processors use around 30 percent less power than their Haswell predecessors, while keeping performance the same or better.

While this is good news for MacBook Pro owners, simply using Broadwell versions of the same chips wasn't enough for the new MacBook. Instead, Apple turned to an even lower-power option, Core M.




Where the Core i5 found in the MacBook Air uses 15 watts of power when active, the MacBook's Core M draws just 5 watts. This lower draw also translates to less dissipated heat, which makes it practical for the MacBook to go fanless, eliminating another power drain.

We don't know exactly which Core M chips will land in shipping MacBooks, but the evidence suggests that it will be the 5Y70 (1.1GHz base clock) and 5Y71 (1.2GHz) models. Apple probably won't receive off-the-shelf parts -- the 5Y70 and 5Y71 are rated for 4.5 watts, compared to the 5 watts Apple cites -- but the broad strokes are likely to be similar.

More Efficient RAM

As we noted in our look at the latest 13-inch MacBook Pro, ultra-low-power LPDDR3 RAM has begun to propagate throughout Apple's laptop lineup. It first appeared in the 2013 MacBook Air, and is likewise featured in the new MacBook.

LPDDR3 was originally developed for use in smartphones and tablets, and as such is architecturally different from DDR3L, which is a low-power version of traditional desktop RAM that's often used in laptop computers. Aside from requiring lower I/O voltage -- LPDDR3 runs on 1.2 volt HSUL, versus 1.35 volt SSTL for DDR3L -- LPDDR3 also sips power while in standby.
In standby mode, LPDDR3 uses just 10% of the power of desktop DDR3.
LPDDR3 is designed to operate at 70 percent of the power required of traditional desktop DDR3 while active. In standby, that drops down to just 10 percent.

Compare that to DDR3L's 85 percent across the board, and the power savings become obvious.

Curiously, Apple doesn't provide any data on the standby time for the new MacBook, a stat that it trumpets on the MacBook Air. It's unclear why that's omitted, but it will be interesting to see how it stacks up to the 30 days of standby on the Air.

Other Contributors

While the new Retina display, Broadwell chips, and LPDDR3 RAM seem to be the most important factors in the new MacBook's impressive battery life, they aren't the only ones.

The addition of 802.11ac Wi-Fi, for example, could help by completing network requests more quickly, allowing the radio to return to low-power standby mode faster. This is the same basic concept that gives mobile phones better battery life when using LTE, even though the radio itself uses more power.

The MacBook's redesigned keyboard could also play a role. Rather than using a single set of LEDs with a plastic diffuser as older models do, Apple has placed an individual LED under each key in the new MacBook. This might allow for advanced energy management options, like more granular backlight intensity or varying the light level of individual keys based on their importance.

And, of course, Apple's new terraced batteries -- which AppleInsider will take a more in-depth look at later this week -- allow the company to pack in more capacity than they would have been able to with traditional designs.

We won't know the full story until the new MacBook ships, but from the outside looking in, Apple seems to have hit the power efficiency ball out of the park.
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Comments

  • Reply 1 of 112
    I believe the 13" MBP also switched to LPDDR3 with this latest refresh.

    The MacBook is a technological marvel, one I'm glad to see. If I were after a new Mac laptop, I'd get one.
  • Reply 2 of 112
    mac_dogmac_dog Posts: 915member
    i'm not a spelling or grammar police member, but i feel like the headline is misleading. the way it is written, "the new macbook gets almost as much charge as a macbook pro whose batter is half the size."

    meaning that the new macbook battery is twice the size of the current macbook pro and is not even getting the same amount of charge. that's how i read it anyway%u2014at first glance.
  • Reply 3 of 112
    cash907cash907 Posts: 893member
    Not surprising. This thing is more tablet with huge battery than laptop. Not saying that's a bad thing, just is what it is.
  • Reply 4 of 112
    solipsismysolipsismy Posts: 5,099member
    cash907 wrote: »
    Not surprising. This thing is more tablet with huge battery than laptop. Not saying that's a bad thing, just is what it is.

    Except that it 1) has no touchscreen, 2) has a built-in keyboard, and 3) runs a windowed OS. :roll eyes:


    edit: To my block list you go.
  • Reply 5 of 112
    By Apple standards 9 hours of battery life isn't impressive. Pretty much all of their tablets and laptops get at least 9 hrs or more. I was actually disappointed to hear that the MacBook's battery life gets less battery power then the MacPro with Retina, considering it has a smaller screen, less powerful processor, less ports, and lighter weight.
  • Reply 6 of 112
    wa4321wa4321 Posts: 8member

     

    Quote:

    Originally Posted by mac_dog View Post



    i'm not a spelling or grammar police member, but i feel like the headline is misleading. the way it is written, "the new macbook gets almost as much charge as a macbook pro whose batter is half the size."

     

    nope, your defiantly not... the title isn't written that way at all.

     

    How Apple's new MacBook gets nearly as much battery life as the MacBook Pro with a battery half the size

  • Reply 7 of 112
    carthusiacarthusia Posts: 579member

    It's clear that Apple's hardware teams have pretty much a blank check to design the absolute best possible machines. I really don't think ANY other personal computer company's hardware division is even close to having this type of freedom-even if they had the talent.

  • Reply 8 of 112
    mstonemstone Posts: 11,510member
    Quote:
    Originally Posted by SolipsismY View Post





    Except that it 1) has no touchscreen, 2) has a built-in keyboard, and 3) runs a windowed OS. :roll eyes:

     

    I don't know. It is getting closer. I don't think anyone here doubts that in the Apple labs somewhere, there is a version of OS X running on ARM. They are just not quite ready to spring that on the third party developers like Adobe, Pixelmator, Parallels, Fusion, Microsoft, etc. But even Adobe is probably almost ready as they must suspect the same thing, especially since they are working on iOS apps that are similar to their desktop apps. Personally, I think it is inevitable that we will see super low power consumption ARM based Macs soon. I'm also confident the higher end Macs will continue on Intel for the foreseeable future.

  • Reply 9 of 112
    carthusiacarthusia Posts: 579member
    Quote:

    Originally Posted by SolipsismY View Post





    Except that it 1) has no touchscreen, 2) has a built-in keyboard, and 3) runs a windowed OS. :roll eyes:





    edit: To my bock list you go.



    I didn't think the comment was troll-ish or off the mark, but that's just me. Apple appears to have applied a lot of what they learned designing iPad and iPhone to making this machine.

  • Reply 10 of 112
    zroger73zroger73 Posts: 779member

    I don't even need to read this article to tell you this is like putting a chainsaw engine in a dump truck - it'll run a lot longer on a tank a gas, but it won't get much work done!

  • Reply 11 of 112
    Quote:

    Originally Posted by mstone View Post

     

    I don't know. It is getting closer. I don't think anyone here doubts that in the Apple labs somewhere, there is a version of OS X running on ARM. They are just not quite ready to spring that on the third party developers like Adobe, Pixelmator, Parallels, Fusion, Microsoft, etc. But even Adobe is probably almost ready as they must suspect the same thing, especially since they are working on iOS apps that are similar to their desktop apps. Personally, I think it is inevitable that we will see super low power consumption ARM based Macs soon. I'm also confident the higher end Macs will continue on Intel for the foreseeable future.




    No one cares about Adobe, they're a crappy company. Pixelmator runs fine on ARM. Parallels and VMWare would be pointless. As for Microsoft, they already have a full-blown version of Office 2013 that runs amazingly well on ARM. It wouldn't be hard to add in the 2015 tweaks and sell that if necessary;

  • Reply 12 of 112
    mstonemstone Posts: 11,510member
    Quote:

    Originally Posted by TheWhiteFalcon View Post

     



    No one cares about Adobe, they're a crappy company. 


    You are out of touch my friend. Have you seen their stock price lately? Somebody cares.

  • Reply 13 of 112
    solipsismysolipsismy Posts: 5,099member
    carthusia wrote: »

    I didn't think the comment was troll-ish or off the mark, but that's just me. Apple appears to have applied a lot of what they learned designing iPad and iPhone to making this machine.

    Sure, just as Apple used what it learned from Mac and iPod HW and SW to create the iPhone which then used what it learned from the iPhone HW and SW to create the iPad and help shape the Mac. That doesn't mean the new MacBook is tablet-esque. As previously noted, it has zero aspects that define a device as a tablet.
  • Reply 14 of 112
    Quote:

    Originally Posted by mstone View Post

     

    You are out of touch my friend. Have you seen their stock price lately? Somebody cares.




    GTAT had a great share price too. Look how that ended up.

  • Reply 15 of 112
    solipsismysolipsismy Posts: 5,099member
    mstone wrote: »
    I don't know. It is getting closer. I don't think anyone here doubts that in the Apple labs somewhere, there is a version of OS X running on ARM. They are just not quite ready to spring that on the third party developers like Adobe, Pixelmator, Parallels, Fusion, Microsoft, etc. But even Adobe is probably almost ready as they must suspect the same thing, especially since they are working on iOS apps that are similar to their desktop apps. Personally, I think it is inevitable that we will see super low power consumption ARM based Macs soon. I'm also confident the higher end Macs will continue on Intel for the foreseeable future.

    1) I've been suggesting that possibility for years here, and it hasn't been accepted well until recently. Most recently I speculated that the reason for the reemergence for the MB isn't to get rid of the MBA, but so that later on the MBA can be given the 12" MB form factor but with an A-series SoC running either Mac OS X or some Mac OS X-based OS.

    2) A Mac or Mac-like machine running an A-series chip would still not make it a tablet. A tablet can run Intel, AMD, ARM, or any other CPU architecture.
  • Reply 16 of 112
    mstonemstone Posts: 11,510member
    Quote:
    Originally Posted by TheWhiteFalcon View Post

     



    GTAT had a great share price too. Look how that ended up.


    Adobe has been in business 25 years with an amazing record of innovation and always a strong balance sheet. GTAT, not so much. Not even close to being in the same conversation.

  • Reply 17 of 112
    Quote:

    Originally Posted by mstone View Post

     

    Adobe has been in business 25 years with an amazing record of innovation putting out products that sometimes work if they feel like it, and always a strong balance sheet.


  • Reply 18 of 112
    mstonemstone Posts: 11,510member
    Quote:
    Originally Posted by TheWhiteFalcon View Post

     

    Be a man and make your own comments. Don't **** with mine.

  • Reply 19 of 112
    aaronjaaronj Posts: 1,595member

    I really wish I had a justification to get one of these.  They look like really well-though out pieces of technology, and they sure are pretty.

     

    Eh.  Maybe an idea for a justification will come to me in the middle of the night at some point. :)

  • Reply 20 of 112
    magman1979magman1979 Posts: 1,240member
    Quote:

    Originally Posted by mstone View Post

     

    Be a man and make your own comments. Don't **** with mine.




    Sorry to say, his "modified" comment is 100% spot-on... Also, I think it meant with a little bit of sarcasm, so don't take it too seriously. I've done that to people here, and people here have done that to my comments, can't get so worked up about it...

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