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  • Writer's pictureMatt Ferguson

Your laptop’s advertised battery life is a lie

Windows laptop manufacturers have dramatically overstated battery runtimes, for years

With the sole exception of Apple, every single laptop manufacturer has lied, consistently, about their laptops’ battery life. As a study from Digital Trends found in 2017, Apple actually overstated the battery runtime of their MacBook Air 13”, claiming a 10-hour battery life while Digital Trends’ testing found the MacBook ran for 12 hours.

In this instance, Apple is the only winner. Every manufacturer of Windows laptops was found to have overstated (if we’re being generous) or lied about (if we’re being honest) battery life. Dell was found to have overstated their battery life figures to the tune of 4 hours, while HP overstated battery runtimes by almost 5 hours.

When probed for comment on these vast discrepancies, Dell told Digital Trends:

“It’s difficult to give a specific battery life expectation that will directly correlate to all customer usage behaviors because every individual uses their PC differently,”

Dell’s statement is a cop-out, at best; every Windows laptop manufacturer will no doubt provide a variation of the very same statement Dell gave on the subject of battery life. We can say, authoritatively, that their response to Digital Trends is a complete misdirection. What Dell fails to acknowledge is that battery life tests are generally synthetic and not based on real-world workloads (such as web browsing, video editing, or software development). Let’s dig into what exactly these synthetic battery life tests are and why they are absolutely worthless for providing any useful insight into a device’s real battery life.

UL Solutions (Underwriters Laboratories), publisher of various computer benchmarking applications, offers what they describe as a standardized battery life test within their PCMark10 benchmark suite. The battery life testing portion of PCMark10 tests laptop battery life under three synthetic workloads: video, modern office, and gaming. Each workload test also generates a power usage report which indicates the wattage used by a given laptop under each synthetic workload. While this standard theoretically allows for independent reviewers and media outlets to test a laptop’s battery life and have directly comparable results to other laptops tested with PCMark10, the reality is murkier.

Owing to battery runtime losses due to battery degradation, changes in runtimes due to firmware and operating system updates, as well as possible battery life fluctuations between operating system versions (eg: Windows 10 versus Windows 11), maintaining a database of reliable battery life numbers becomes a daunting task. This is made worse by the sheer, mind-boggling number of Windows laptops available on the market at any given time. To further complicate matters, some manufacturers sell the same laptop with smaller and larger battery capacity options.

Lenovo, for example, offers two variants of their Thinkpad X13 Gen 3 laptop: one with a 41Wh (watt-hour) battery and one with a 54.7Wh battery. Naturally, the variant with the 54.7Wh battery will produce longer battery runtimes thanks to its larger capacity. The problem is Lenovo’s own website makes it difficult to know which version you’re buying; it’s usually assumed that preconfigured versions of Lenovo laptops with higher end specifications will also include a larger battery, if one is offered. Retailers likewise often fail to publish battery capacity information if none is made available by Lenovo, in this example.

Other online computer review publications, like the seminal, have created their own battery life tests, which are not standardized and can’t be directly compared to battery runtime numbers produced by other reviewers. In Notebookcheck’s case, however, their own test results are consistent and methodologies are applicable to old laptops, reviewed years ago.

Elsewhere on the Internet, one benchmark may specify a 150-nit brightness setting with WiFi disabled for their battery test, while another may specify a 200-nit brightness setting with WiFi enabled. The manner in which battery runtimes are tested is not at all consistent across manufacturers and review outlets.

This maelstrom of non-standardized data allows the laptop makers themselves to claim that there is no truth and that everyone’s experience with battery life will be different. We don’t encounter laptop makers understating the battery life of their laptops–why is that? Better to under-promise and over-deliver, isn’t it? Of course, if Dell, HP, Asus, or Lenovo admitted the average person might only see 4 hours of battery life, they’d sell fewer laptops.

Apple, especially now that it produces its own silicon, is in the enviable position of offering the best battery life in the industry. Windows laptop manufacturers have taken note of this and are willing to beg, borrow, and steal their way to comparable energy efficiency in their own machines. This, realistically, is impossible: Intel and AMD cannot compete with the efficiency of Apple’s in-house silicon (though AMD is currently still ahead of Intel in this regard).

Much of the battery life delta between Windows (x86) and Apple (ARM) is down to architectural differences between x86 and ARM. x86 has existed since 1978 and, while it has grown in complexity since, has not been fundamentally overhauled to address inherent inefficiencies. The x86 architecture contains legacy instruction sets that just aren’t relevant to modern computing workloads. However, this legacy cruft still takes up space on the processor’s die and requires power, whether it’s used or not.

This agglomeration of inefficiencies within x86 has made it harder and harder for processor manufacturers (in this case, Intel and AMD) to produce the kinds of efficiency gains that Apple did by jettisoning x86 altogether. This is why Apple can understate its battery life and no one else can.

As more people find that they can do most, if not all, of their work using web apps and cross-platform apps, Windows starts to become less of a necessity. As a consequence, Windows-based laptops with poor battery life become less of a necessity. Kids in schools across the country have found that they can do their assignments just as easily, if not more easily, on Chromebooks running Google’s ChromeOS, than they can on Windows laptops. Software developers and creative professionals in photography and graphic design have long chosen Apple laptops for their reliability and more focused software offerings. Maybe it’s time for users of other stripes to reevaluate whether Windows and x86 are all that compelling, anymore.

MacBooks are expensive, though perhaps less so than you imagined: the price of entry hovers around $800 for an entry-level MacBook Air with 8GB of RAM and 256GB of storage. This represents a perfectly adequate specification for casual users and office workers. While $800 is appreciably more expensive than the low-end, $300 Windows machines you might find at Walmart, the differences in battery life, performance, build quality, and overall polish justify spending more. A MacBook will yield a much longer usable lifespan than a budget Windows laptop, as well.

Unless a breakthrough happens in x86’s design efficiency, custom ARM silicon (like Apple’s M1 and M2 chips) seem to point the way forward for mobile computing. Regardless of your feelings about Apple’s closed ecosystem and its spendy hardware, Apple does deliver on its battery life promises. Let the PC makers squabble over 5 and 6-hour real world battery life–you’ve got other options.

If you’re in need of a new device or a new fleet of devices for your business, get in touch with Geek Housecalls today and we’ll recommend the best device for your use case, at competitive pricing.

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