Battery Life & WiFi Performance

Last but certainly not least in our look at the MacBook is a look at its battery life and WiFi performance.

Along with the technical considerations that have gone into making the MacBook as small as it is, I would consider the subject of battery life to be the second most interesting aspect of the MacBook’s design. For on the one hand, the CPU at the heart of this laptop is Core M, a very low power CPU specifically designed for thin & light devices, which on its own doesn’t draw all that much power. On the other hand in constructing the MacBook Apple has ditched the MacBook Air’s standard DPI TN panels for high DPI Retina IPS panels. As we’ve seen in other Apple products in the past, going Retina incurs a significant power cost, as the high DPI displays require a much stronger, much more power hungry backlight to light up the display. Apple needs only to pay this cost once, but it’s an expensive cost.

All the while Apple also has to deal with the battery capacity limits of such a small chassis. Using terraced batteries has allowed Apple to maximize the amount of volume the MacBook’s batteries occupy, however at 39.7Wh this only gets them up to roughly where the 11” MBA (38Wh) already sat. The end result is that relative to the 11” MacBook Air Apple has virtually the same battery capacity to drive a less power-hungry CPU and logic board paired with a more power-hungry display.

Officially the MacBook should be able to hit 9 hours of runtime on a light web workload, and 10 hours with video playback. This happens to be identical to what the 11” MacBook Air is rated for, and in practice would be very close to what the Haswell-based 11” Airs hit as well.

Meanwhile to test battery life, we have two workloads. Our light test is light web browsing, and our heavy test increases the number of pages loaded, adds a 1 MB/s file download, and has a movie playing. We set all displays to 200 nits.

Light Workload Battery Life

In practice what we find is that by our testing methodologies the MacBook falls about an hour short, clocking in at 8 hours and 5 minutes. The difference in battery life most likely comes down to differences in how we test; Apple bases their estimates on 75% display brightness, whereas we test at 200 nits, which in the case of the MacBook is around 85% brightness. If we turned our brightness down to 75% I suspect our results would come very close to Apple’s, at the cost of dropping below 200 nits of brightness.

Even by our own testing standards, the MacBook’s battery life is enough to get the laptop through an entire work day (8 hours) – if only just – so while we can’t hit 9 hours at our preferred brightness Apple isn’t in too poor of a position for such a small laptop. In practice what this means is that the MacBook does just a bit worse than the 11” MacBook Air, essentially falling behind by 40 minutes of runtime. However given the fact that the MacBook is also physically smaller than the 11” Air, this is not an unexpected tradeoff.

Putting things in a bit larger perspective, thanks to Intel’s massive energy efficiency gains from Haswell in 2013, the MacBook looks very good compared to the older 2011/2012 11” MacBook Air models. From a battery life perspective the new MacBook easily exceeds those models, is physically smaller than those models, and all the while delivers performance that at worst is equivalent and at best better than those models. Put another way, Apple has been able to hold performance constant while bringing down both the size and greatly improving the battery life.

However if you want better than 8 hours on a light workload, then even the MacBook is no substitute for a larger laptop with a bigger battery. There’s only so much that can be done on 39.7Wh, and as a result the 13” MacBook Air will remain unmatched as Apple’s long-haul Ultrabook.

Heavy Workload Battery Life

Meanwhile with a heavy workload the MacBook’s fortunes improve. No longer just in the middle of the pack, at 5 hours and change it’s offering runtimes close behind the 13” MacBook Airs. This shift in relative performance is not unexpected, and is closely tied to the balance between CPU power consumption and display power consumption. Compared to the light workload, the heavy workload requires that the CPU draw quite a bit more power all the while the amount of power drawn by the display is virtually unchanged. As a result the higher powered MacBook Airs see a big step up in their power requirements, while the Core M equipped MacBook sees a smaller step up.

Heavy Workload Battery Life (As a Percentage Of Light)

In fact if you look at heavy workload runtime as a percentage of light workload runtime, the 2015 MacBook has the smallest drop in runtime out of all of the MacBooks. Apple’s latest laptop gets 62.2% of its light runtime under the heavy workload, compared to 50.1% for the best MacBook Air. The only thing with a similarly small decrease are the Retina MacBook Pros, whose large, Retina displays result in a similar situation.

Somewhat paradoxically then, the MacBook looks best under a heavy workload, even though its processor is relatively slow. Ultimately this is more an intellectual curiosity than anything else, but it’s a great example of how the MacBook’s component selection has resulted in a much different power consumption balance between the display and CPU than what we’ve seen on the MacBook Airs and similar Ultrabooks. If the display isn’t the single biggest power draw on the MacBook, it’s certainly going to be a close second.

WiFi Performance

Our final benchmark is a quick glance at WiFi performance. The MacBook ships with a Broadcom 2x2:2 802.11ac solution, which means that in theory it is capable of delivering up to 833Mbps.

For our WiFi benchmark we copy a large file from a Gigabit Ethernet connected SMB file server, timing how long it takes to transfer the complete file and calculating the average. All laptops are placed within a few feet of the router to maximize their achievable bandwidth and minimize interference. For the MacBook we’ve gone ahead and run this test under both Windows and OS X, to showcase any performance differences between the two OSes.

WiFi Performance - TCP

Under Windows the MacBook hits 389Mbps, about 47% of its theoretical maximum performance. Compared to other Windows laptops this is a mixed bag, with some laptops able to hit as high as 500Mbps, and others coming up much shorter. In the case of the MacBook I suspect the all-aluminum chassis is not doing it any favors. Meanwhile performance under OS X is a bit worse at 333.7Mbps, most likely due to OS X’s less extensively optimized SMB support.

While I imagine it’s impractical from a design perspective, given the fact that the MacBook only has a single USB port, I would have liked to see a 3x3:3 solution for the MacBook to allow it to achieve better WiFi performance. Even 3x3 solutions seldom keep up with GigE in the real world, but the MacBook certainly has the SSD and processing power to handle faster speeds than what we’re seeing here.

Windows Performance Final Words
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  • lilmoe - Tuesday, April 14, 2015 - link

    "I’m going to start where I left off in our introduction, which was the concept of the laptop/tablet crossover. The idea of laptops and tablets crossing over is no longer merely an idea, but now it is reality"

    Yea. Back here, we call those "Netbooks". But "crossover" sounds cooler.
    Reply
  • darwinosx - Tuesday, April 14, 2015 - link

    You don't know what a netbook is. They were cheap devices with low quality screens and poor build quality. Try reading the review you are commenting on. Reply
  • lilmoe - Tuesday, April 14, 2015 - link

    OK, so it's a better quality netbook. Got it :P Reply
  • vFunct - Tuesday, April 14, 2015 - link

    Sorta like how a laptop is a higher quality netbook.

    Or, how a computer is a higher-quality calculator.
    Reply
  • PEJUman - Tuesday, April 14, 2015 - link

    Maybe in 2012 laptop is higher quality netbook. I am starting to feel that Anandtech is getting too 'careful' with the OEMs. M9 is bad, call it that. this Macbook fits squarely in the netbook term from functionality standpoint, despite the price premium for the fit and finish. No need to redefine a new 'crossover' term just to keep Apple marketing managers happy.

    Right now, chromebook and other ultraportables (such as this one) with the relatively slow core M are the de-facto sucessor to netbook. Single usb port also a netbook typical compromise. It not convertible nor it has a touchscreen, so.. NETBOOK.

    Tech evolves, therefore performance expectation should evolve with it. the core M is barely faster than a 2012 intel i3-3217U on geekbench. It is the lowest performance tier of Intel big core family.

    Anandtech used to be unbiased, I think they finally started the slow descent towards 'marketing for OEM'. I understand where this is coming from, and I am willing to pay for anandtech subscription if that what it takes to restore the one place a techie can get an unbiased, deep dive into new techs.

    Purch should differentiate Tom's & Anand by using Tom's for their mainstream, 'marketing compatible portal' while turning Anand into a subscription based portal, with reviews selection based on customer votes, each one completely unbiased, purely technical, pull-no-punches style.
    Reply
  • ws3 - Tuesday, April 14, 2015 - link

    Something like the transformer book is a modern day netbook: atom processor, $300 price, questionable build quality --- all the traits of a netbook. Reply
  • BittenRottenApple - Wednesday, April 15, 2015 - link

    Yet another fine addition to the long list of "Terrible Products Apple Makes to Gouge Money out of People".

    The new MacBook is a testament to Apple's collapsing technical acumen. They eliminate all ports except for one outdated USB port? This craven stupidity should send the last adherents running. But running to what? Windows isn't even a viable option anymore, since it now is the most widespread commercial NSA gathering tool available, closely followed by Android, iOS and OS X.

    It's a sad day for people who need real computers. Jony Ive is a pompous, clueless hack who should be fired for introducing crippling regressions like this one.

    Look at this POS: One USB port, which will require an adapter to do anything. So if you're going to require an adapter anyway, why not make that one port a modern one: Thunderbolt. Thunderbolt can carry USB, video, Ethernet, external storage... ALL AT ONCE. And it can be daisy-chained, which is hugely important when the computer has ONLY ONE PORT. So WTF is Apple doing making its sole port USB?

    And again, are you kidding me? One tiny USB connector? Now every sorry user of this pos has to find a thunderbolt to USB C, a USB C to USB to HDMI, a USB to USB 3.0 period, a USB C to USB connector for apple’s time machine and also manage to don't short circuit all that with the AC/DC to USB C connectors, seriously ? Worth 200$ new pile of hairy connectors for the brand new gold macbook air, and that is called a revolution nowadays? No ********** way, the Dell XPS 13 is way superior, period.

    By the way, they're perpetrating USB Type C connectors. Thunderbolt is a much-needed step to a modern I/O standard. USB is an outdated, abused standard that was designed for keyboards, mice, and modems. It's not suitable for external storage, video, or anything else requiring bulk data transfer with minimal CPU overhead. USB C is a regression, a major step BACKWARD.

    $1599.99----Less than $550.00 worth of hardware = ~$1000 premium to use OS X instead of windows. (Honestly the most expensive component of this computer is probably the screen.)
    Anyone with real work to do will not even be able to buy this thing. My friend’s last Air was neat in that it was small and lasted all day, but it was so under-powered, it was frustrating. I can only imagine how limited this machine will be.

    Who cares about price, weight and size, when this product is crippled by a hopelessly defective design? You can't hook up a power adapter and external storage at the same time. You can't hook up an external display and external storage. Hell, you can't even plug in a thumb drive!

    This product is the most asinine piece of shit Apple has produced, and that includes the (thankfully) short-lived Shuffle that could only be controlled by a gimped Morse code.

    $700 less gets you the new Dell XPS 13 which will eat the Mac's lunch.

    If you need to do a lot of processor intensive work, than you would not even go near this thing. It would be useless to you. If you need to crunch spreadsheets or are heavy in corporate analysis, this computer would also be useless to you.

    This is the kind of computer that Apple sells a lot of. This computer is largely useless for anything other than email and facebook. It cannot store many files, it cannot process much information, and it has one external port. There is nothing wrong with using this computer for casual tasks, but it is CERTAINLY not a productivity machine.

    It is what it is. A status symbol/statement. Or some other statement. A statement that you just bought a $400 netbook with a $900 case so you can show off in front of your hipster friends.

    I hate to stick to Apple only facts here, but Apple said that the Air is 24% thicker than this new Macbook. That does NOT mean that the new Macbook is 24% thinner than the Air, it means that it is ~20% thinner than the Air. They clearly phrased it that way to make it sound more impressive and hence dupe the consumer, aka stupid isheep.

    So, it's an iPad plus with a keyboard and an over expensive dongle so you can do everything a Dell can do, at twice the price while looking posh.
    And here I thought technology was about function over form. I get it, functional art; art I can do things my phone does, but in a space that anyone can see me doing it, stylishly. Crippled and non standard in-house branded "business" software does great, can't do anything really artistic on it except maybe GarageBand or stock filter photo edits to my innumerable selfies, but it's got that partially eaten fruit on the back that screams "money I'm too stupid to keep or invest wisely."

    Take my money!
    I wouldn't hold my breath.

    This is apple's marketing strategy: mind-numbing markup on dirt-cheap, mediocre laptops. They throw together a cheap little laptop, pretty it up with silver or gold paint, and ride the wave of ignorance, outrageous markup, and marketing that they've been using as a business model for many, many years now. The only thing Apple has ever made that's less worthless than all the other crap their conspirators like Hon Hai Precision Industry Co., Ltd excrete all day and night by taking advantage of child labour are iOS and OS X which, besides being notoriously crippled and constrained walled gardens, aren’t even worth the hassle unless you also dumped thousands of dollars into other apple products.

    Many apple owners I’ve encountered never stop trying to belittle and demean others because they don’t have a Macbook or an iPhone and then try to act like their overpriced apple products are overall better when they are certainly not, by any standard.

    Luxury cars, while still worthless crash grabs, usually offer some quality and features that are actually somewhat superior to cheaper competing brands and models.
    Macbooks such as this start already expensive as hell with little performance to warrant such outrageous costs. Apple isn’t the luxury car of anything. It’s the luxury car DESIGN with a 4-cylinder under the hood and a tape-deck in the sound system, all with the price tag of "luxury". They sell laptops made cheap in china, using child labour and the same hardware you can find in SO many other laptops, slap their OS on it, put it in a thin case, and then markup the price by 300% to 600%. These are the facts. This laptop in question is nowhere NEAR worth that kind of money. I mean, laptops in general are overpriced, but apple has made their entire business model out of extreme markups backed by clever marketing with little actual technological superiority of any kind. Every single apple product on the market can be outperformed in every way by comparable products. Apple computers can be outperformed by computers that are FAR FAR cheaper while relying on older tech. The only thing that apple has that nobody else does is OSX and iOS, their operating systems. These are mediocre operating systems, but they are literally designed to be limited on anything it determines to be "non-apple hardware". Other operating systems can be installed on just about any computer you can slap together, whereas OSX is specifically and deliberately designed to be non-functional on ANYTHING that isn’t made by apple. It’s nothing but a cash-grab.

    Apple is indeed playing run-of-the-mill capitalism, they try to capitalize on the ignorance of the average consumer with marketing campaigns designed to make you assume you're getting your money's worth.

    There are millions of consumers who are on the fence, who are actually interested in buying something that's worth the money they spend. Those people deserve factual information and do not deserve to be exploited for their ignorance on the topic. So excuse me if I have a problem with it. College students especially, who don’t have a lot to spend in the first place, are being taken advantage of in every area of their life. Buying a computer should be one less area of exploitation. This is why I have a problem with apple and with many other companies and services that attempt to capitalize on ignorance.

    Years down the road when the batteries in this model are dead and you have to keep it plugged in just to use then you'll have no way to plug in a flash drive or an external hard drive. I don't care how sexy it looks: sometimes and more often than not less means a serious lack of functionality.

    We can only hope that consumers send this piece of diabolic garbage to oblivion, as they did the idiotic iPod Shuffle that could only be controlled with Morse code over a proprietary headphone wire.
    Reply
  • Notwist - Wednesday, April 15, 2015 - link

    You literally just typed a small novel spewing a bunch of claims without citing anything to support your arguments, or outright fabricating stuff. It's the absolute definition of a poorly written, complete waste of time. Please take your rants elsewhere, Anandtech readers, last I checked, enjoy discussing tech, not spouting conspiracy theories and raving like lunatics. Reply
  • superflex - Thursday, April 16, 2015 - link

    I thought it was quite good.
    You sound like a butthurt iFanboi
    Reply
  • star-affinity - Friday, April 24, 2015 - link

    I thought it was bad and not nuanced at all. Things aren't that black and white. Reality comer in many shades.

    People have the right to have an *informed* opinion. The long post above is unfortunately based mostly on ignorance.
    Reply

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