Samsung Galaxy S9 battery problems, explained: Exynos vs. Snapdragon

New phones should have better battery life than their predecessors. That's a given, and part of the unspoken rule of technological progress. And yet in recent years that hasn't been a given. Along the way, we've seen blips — Snapdragon 810, anyone? — on the way to greater efficiency.

This year, the culprit is Samsung's Exynos 9810, the ultra-fast chip that ships with all Galaxy S9 and S9+ units outside of the U.S. Samsung's new custom M3 cores inside the phone are clocked extremely high, up to 2.7GHz when only one of the four performance cores is engaged, and that, according to an excellent overview by AnandTech, ramps up the voltage (and the heat output), causing it to churn through the Galaxy S9's battery like a raccoon through garbage.

Technically, there is nothing surprising about this — the Exynos 9810's M3 cores are extremely powerful, besting Qualcomm's proprietary Kryo cores by a large margin in synthetic tests like Geekbench. But Samsung appears to have failed the task of balancing real-world performance with device longevity, and given Android's scalability, such theoretical performance advantages are not always borne out in the mundanities of daily tasks.

In other words, it looks like the Exynos 9810 is a battery dud. Here's what AnandTech's Andrei Frumusanu had to say about the chip:

In a vacuum, the Exynos 9810 could be seen as a good improvement over the Exynos 8895. However Samsung LSI isn't only competing against itself and iterating on its products, it needs to compete against ARM's ever-evolving offers as well. Unfortunately it feels like S.LSI keeps being one generation behind when it comes to efficiency – the A72 beating the M1, the A73 beating the M2 and now the A75 beating the M3.If you were to shift the microarchitectures one year ahead in Samsung's favour then suddenly we would have had a much better competitive situation. Currently a 17-22% performance lead does not seem worth a 35-58% efficiency disadvantage along with the 2x higher silicon area cost.

To summarize, the chip used in the majority of the world's markets is around 20% faster than its predecessor, but in some cases over 50% less efficient. This isn't theoretical, either:

The Exynos 9810 Galaxy S9 absolutely fell flat on its face in this test and posted the worst results among our tracking of the latest generation devices, lasting 3 hours less than the Exynos 8895 Galaxy S8. This was such a terrible run that I redid the test and still resulted in the same runtime.

Strategy Analytics, 2018

Strategy Analytics, 2018

Separate tests from Strategy Analytics, an independent research firm based in the UK, show that AnandTech's results are not unique: the Exynos Galaxy S9 measured a 25% battery disadvantage compared to SA's leader, the upcoming Sony Xperia XZ2 (though it must be said that Sony commissioned the test).

The reason for Samsung's poor showing isn't because the Exynos 9810 is a bad chip, or even that it's inherently power-hungry; it appears that Samsung merely programmed the core scheduler poorly, resulting in clock speeds and voltage settings that aren't appropriate for the task at hand. Again, AnandTech:

When looking at the power curves correlated with our traditional integer power virus we see that there's an immense increase in power consumption at the higher frequencies. Indeed going from 2.3GHz to 2.9GHz would have doubled power usage, and even 2.7GHz comes at a steep power price. Given that power usage scales roughly along the lines of voltage cubed, the SoC's efficiency suffers with the increased frequency. The good news here is that Samsung's efficiency curve is quite steep and linear, that means backing down on frequency should see significant efficiency gains.I've had a look through Samsung's scheduler and DVFS mechanisms which controls the switching between the 1/2/3/4 core modes and generally I've been unimpressed by the implementation. Samsung had made use of hot-plugging to force thread migrations between the cores which is an inefficient way of implementing the required mechanism. The scheduler is also tuned extremely conservatively when it comes to scaling up performance, also something we'll see the effects of in the system performance benchmarks.

To (mis)use a car analogy, the S9 has been programmed to use the wrong gears for the task at hand, burning fuel at times when the car could be cruising, and puttering along on a single cylinder when two or more are needed. This is theoretically fixable with a firmware update, but Samsung must have done extensive testing of the Exynos-based S9 before shipping it to consumers, and this looks really bad, especially when it is also shipping U.S. and Canadian models with the extremely efficient, altogether improved Snapdragon 845.

In a recent essay, my iMore colleague, Rene Ritchie, made a good point about Samsung's divided focus:

Having two silicon targets just means, as opposed to infinite time, you have half the time to optimize for each.

He is referring to the fact that Samsung Electronics builds the same phone using system-on-a-chip components from two companies: Samsung LSI, which operates independently from its parent company, and Qualcomm, which designs the Snapdragon 845. There are a number of reasons for this division, and some would argue that it's Qualcomm's fault that Samsung is in this position at all (you can catch up on that story on your own time), but the reality is that Samsung's attention is divided, and it may not have devoted the necessary resources to properly optimizing the Exynos-equipped S9 to achieve the same combination of performance and battery longevity that customers expect.

One can also safely make the assumption that a company like Samsung LSI is trying to bottle the same kind of magic that Apple has achieved with its A-series chips, which still dominate many of the same synthetic benchmarks that Samsung attempts to dominate by ramping up peak speeds. Apple's silicon advantage isn't nearly as cut-and-dry as many Apple pundits would like to present it — Android's silicon flexibility requires being able to scale to levels of performance that Apple has never needed to achieve with iOS — but there's no question that on a high level, Apple's in-house silicon team is ahead of the competition. AnandTech again:

What needs to happen with the [Samsung] M4 is a much larger efficiency boost to remain competitive with ARM's upcoming designs and actually warrant the use of an internal CPU design team.

Qualcomm, on the other hand, appears to have another successful product with the Snapdragon 845: it's slightly faster than its predecessor without regressing in efficiency, so the U.S. variant of the S9 appears to offer slightly better battery life than the S8. The Galaxy series has never excelled in uptime, but there's never been such a gulf between Samsung's two versions, until now.

Leaving aside the complicated technical aspects of the story, this is nothing but a bad-news story for Samsung, as it wants nothing more than to make customers believe they are buying the same phone wherever they happen to live. Samsung goes out of its way not to specify the processor in the Galaxy S9's marketing (opens in new tab), and for good reason. Many of Samsung's millions of customers will know the differences, and subsequent advantages or disadvantages, of the two SoCs, but most will not.

What Samsung risks, however, is providing an experience that those unwitting owners would consider sub-optimal, with battery life less than its last-generation product, and a gaping maw of real-world battery life tests between the U.S. and the rest of the world.

Let's hope a fix is in the works.

Daniel Bader was a former Android Central Editor-in-Chief and Executive Editor for iMore and Windows Central. 

  • I'm just happy we got the good one for once.
  • Well there is no way Samsung was unaware of this so they deserve the bad press and unhappy customers. Everyone should have gotten the 845.
  • Why do I keep hearing things about how powerful the Exynos 9810 is and how it trounces the 845 but every test I've seen dictates otherwise?
  • It does really well in synthetics like geekbench. However, due to a scheduler that takes super long (close to half a second) to turbo up to max clocks when a load is given bursty loads like web browsing suffer a lot. As well, my understanding is that whenever a new thread comes onto a core it has to re turbo up for some reason, which is really inefficient. If you want a better explanation, I highly recommend reading the end of the system performance section of anandtech's s9 review
  • I can't complain, I use mine s9+ daily and only need to charge him after 2 full days and i'm using the Exynos model(living in Belgium)
  • Must not use it very much.
  • My wifes exynos s9+ is at 74% battery after 11 hours. Seems allright for normal usage.
  • Unless you compare it to the Snapdragon in the U11 for example, which after a hard day including Google Maps navigation, is at 82% after 16 hours.
  • The U11 had pretty solids battery life
  • The exception would be between the January and March updates. The January update did some bad things with battery life, but the March update made it better than ever. Ironically, I noticed that the S9 in the article photo is at 71%, and right this moment my U11 is also at 71%... except I forgot to charge it last night and it's been 30 hours of runtime! I really hope battery technology takes a big jump. A smartphone that can go 10 days with full use would be awesome.
  • Hi fella, seen you mention this before, is it the standard U11 or the plus? Epic battery life.
  • Well, it's about time that the people with the Snapdragon version didn't get the short end of the stick, since that was definitely the case with the S7 and S8. Of course with the S6 Samsung used the Exynos chips everywhere because the Snapdragon 810 was such a ****. Actually glad to have the Qualcomm version, for once. Now, about their being no other option in the US market aside from the 64Gb base storage variant...... EDIT: What a joke, you people actually edit the word t-u-rd? FFS, that's pathetic. 🤦🏻‍♂️
  • "F*S, that's pathetic." Fixed that for ya.
  • Lol 😂, thank you very much, I overlooked that. I'm sure that these stalwarts will make adjustments to compensate. *🤬*
  • Wasn't the case with the s8, I believe the Snapdragon was better. Definitely true of the s7 though
  • I have the exynos version 9b plus and the battery life is savage on it, much better than my S8 plus
  • I'm not sure if you guys read the Anand article a little further. It's stated that many of the issues arise when the chip is allowed to work hard. By using the speed limiter as part of the plethora of power saving options, the battery life improved but only barely over the 8895. I have a feeling they have not completely optimized either the scheduler or more likely, the actual SoC to use power as efficiently as possible. The SD845 version this time seems to be the better all-rounder.
  • "Apple's silicon advantage isn't nearly as cut-and-dry as many Apple pundits would like to present it — Android's silicon flexibility requires being able to scale to levels of performance that Apple has never needed to achieve with iOS..." To use another car analogy, this is like saying "BMW's engine advantage is not as cut-and-dry as many BMW pundits would like to present it - Chevy's engine flexibility requires being able to scale levels of performance BMW has never had to achieve with its engines..." That doesn't change the fact that BMW makes better engines than Chevy, LS-designated V8's notwithstanding. I say this as an Android guy; you just can't deny that Apple makes better silicon than anyone else.
  • Actually apple makes nothing but software. They design alot of stuff and farm out foxconn and even samsung to "make" things for them. And since apple has complete control over the software and how the hardware is built they can optimize much better. Android being open source and supporting hundreds of oems cant ever hope to have that level of optimization. But choice is a lovely thing......and my head doesnt fit in apples box. Id rather go back to a flip phone than give apple my money
  • Car analogy isn't really a good fit here. Scalability isn't about quality; it's being able to manipulate clock speed and core activations. For example, I'm looking at the CPU graphs on my current phone, and the CPU speed varies smoothly from 0.1 GHz to 2.45 GHz. The result is that the CPU clock speed can be scaled more precisely to load demands. If you do want to go with a car analogy, think more along the lines of throttle control. One car is faster, but only lets you go 0, 50, 100, or 200 MPH. The other one lets you go whatever speed you want. Quality is not the issue, control is.
  • Which CPU runs at 0.1 GHz? I have not seen a modern CPU run below 500 MHz. 100 MHz is getting dangerously close to analog components and bus, not to mention being slower than RAM. Usually you see the lowest frequency starting around 400 Mhz for any CPU post 2010.
  • Why does Samsung use different chips in the US market? Is it for legal or technical reasons?
  • I think they do it because the Qualcomm chip has all the LTE radios needed for use in the U.S. idk if there is another reason besides that
  • That's my understanding. To sell in the US requires a higher payment to Qualcomm and once you factor that in, it's cheaper to go Qualcomm in North America. Now if that's fair, we'll see how Qualcomm's fate plays out in multiple court cases.
  • It is due to a 25 year licensing agreement Samsung signed with qualcomm in june/july of 1993 that forbids Samsung from distributing its exynos chips in the Us.It ends this year and I'm not quite certain if Samsung would have reasons and motivations to sign the contract again. It will most likely abandon qualcomm and replace its chips in Samsung phones with its own starting in 2020. The first move they've done that shows they're on the road to ditching qualcomm is with the 5g lte modem,Samsung is currently developing their own modem and will end up using it in their devices. They've already been rumoured to have shown the modem in action behind closed doors at ces this year with overwhelmingly positive reactions from those who have seen it.
  • Samsung distributed Exynos chips in the USA with the S6 range. The actual reason Samsung uses Snapdragon normally is the CDMA is Qualcomm proprietary tech and only their SoCs have built in CDMA modems. For an Exynos SoC to be CDMA compatible it needs a seperate CDMA modem which is not as efficient.
  • The main reason why Samsung used its exynos chipset In the Galaxy s6 is because the snapdragon was an overheating pile of crap and using that cpu would tarnish the reputation of the company,they were forced to use their cpu to avoid getting involved in the same overheating fiasco many other companies using the 810 got into at the time. The real problem which prevents Samsung from using its exynos chips in the us,is an unearthed licence agreement between Samsung and qualcomm signed in 1993 with a duration of 25 years the agreement ends this year, after which Samsung will be free of qualcomm's regional restrictions.The exynos 7420 used in galaxy s6 in 2015 ended costing Samsung profits which caused the company to loose profits with each sale as they had to pay qualcomm ridiculous amounts of the profits they raised to use their cdma modem in the us
  • Battery life has been the big disappointment for me with the S9+. I figured the 845 would be an improvement on the 835 and my real world experience has been the opposite. It's been a real bummer.
  • Agree 100%. Battery on my 845 9+ has been abysmal at best.
  • Qualcomm pretty much runs the US and theyd have to pay a licensing fee to use their Exynos chips there. It's cheaper to just use the 845. But the S6 proves they would go all Exynos if they needed to.
  • Oh my...Samsung is in trouble again...
  • Unlike Samsung to put out a bad chip, I think they were so bent on beating an A11 chip this year, that they sacrificed too much raw power and forgot about efficiency. A battery life comparison with snapdragon would make a good read.
  • I'm happy with my 6 month old Note 8. It seems like a crap shoot buying a Samsung phone now. It shouldn't be given the price tag. More testing, BEFORE releasing the new model should be a given.
  • I am using the s9+ Exynos version and I don't experience any battery drain or performance problems at all. I use my phone way too much and I am surprised how long the battery lasts. Even with excessive gaming my battery life is good. Strange how not everyone is experiencing this drain issue and even the SD 845 version is getting mixed battery usage results and reviews.
  • « Apple's silicon advantage isn't nearly as cut-and-dry as many Apple pundits would like to present it — Android's silicon flexibility requires being able to scale to levels of performance that Apple has never needed to achieve with iOS » Well that’s actually a positive !! Remember when samsung attacked Apple on battery life lol
  • S9+ owner here. Battery life is superb compared to my old iPhone 7Plus. Still have 61% left today after taking it off charge 14hrs ago. I'm not the heaviest user (Surf, email, chat throughout the day) but by now my iPhone would have been 25% or less. Performance wise I couldn't be happier. Maybe the S9+ is configured differently to the regular S9.. or.. synthetic benchmarks don't mimic real life usage. Either way I'm not panicking just yet!
  • "This year, the culprit is Samsung's Exynos 9810, the ultra-fast chip that ships with all Galaxy S9 and S9+ units outside of the U.S." Is Canada part of the USA now?
  • "Is Canada part of the USA now?" As far as Samsung is concerned, yes it is.
  • As already said at AnandTeach the scheduling is done horrible on Exynos 9810 variant & not so good either on Snapdragon 845 one either. The Sony wins clear as they apply minimum used active cores with tight task packing per core strategy. This ain't a very good one either as it hurts responsiveness the most. All other OEM's go with no task packing and load balancing when it comes to Snapdragon which is also CAF-s default along with aggressive interactive scaling mostly with out any hotpluging. I find both ways wrong as medium core count always idling so that up down transition can be more swift & medium task packing so that sleeping ones get up less common unless really needed & again with better timing compared to tight packing. Interactive should follow original load logic limits (with increased IO is busy calculations) with couple implemented brakes (on idle frequency so that it doesn't fire up on small loads & white noise, optimal regarding leakage on given manufacturing process and the one sustainable per two big cores [on the big cluster only]) with higher load points & naturally with the hotplug in use set to keep always while device is active a pair of each core's active (or active idling). This if implemented correctly gives better results & it's a sweet point between performance and power efficiency.
  • USA USA USA!!!! ;)
  • It would be great if the author of this article would write to Samsung to see their response
  • The answer would probably not be interesting : "We care about our customers and do our best to satisfy them. We want our customers to be happy with Samsung products and all of our smartphones go through a series of tests to make sure that they are safe to use, and provide our customers with the best experience bla bla bla bla bla..."
  • Huawei seem to be ok with their batteries.
  • "The Galaxy [S] series has never excelled in uptime"
    Yes it has, remember the Galaxy S7 Edge ?
  • The galaxy s5 wasn't a slouch either if I remember correctly.
  • Done with Samsung. Stupid expensive. Completely broken customer service. Ongoing design issues year after year - on only marginal (stepped) tech advancement. Suckers will continued to be sucked (in).
    Not me.
  • benchmark vs real life usage..... 99.9% of people wouldn't notice and couldn't give a ****
  • My Snapdragon S9+ gets pretty terrible battery life as well. Can't fathom the Exynos being worse. My P2XL gets far greater runtime.
  • I have both the Pixel2 XL and S9+(Snapdragon). I'm averaging over 6hours of SoT and around 16-18 hour w day. Same apps. locations with the Pixel I am getting a little less. I'm very happy with the S9+ so far.