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AMD — "We're Not Entirely Honest" About Batteries
Posted by
CmdrTaco
on Mon Mar 16, 2009 10:00 AM
from the big-shocker-here dept.
from the big-shocker-here dept.
Slatterz writes "In an apparent attack of the bleeding-obvious, an AMD rep has come clean and admitted (on behalf of the industry) that notebook and phone battery life figures are completely unreliable. AMD's senior vice president Nigel Dessau says that 'we are not being entirely honest with users about what PC battery life they can expect to actually experience.' He says AMD will now use a combination of idle time (where the machine is left to sit idle, and timed to see how long it takes for the battery to go dead), and 3DMark06 to measure battery life. Great in theory but some of the industry already bases battery figures on a two-test measurement, and the results are still wildly inaccurate."
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Submission: AMD: 'we're not entirely honest' about batteries by Anonymous Coward
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Isn't this simple? (Score:5, Interesting)
1) Fully load the machine
2) Time until battery death
3) Advertise "minimum" battery life
What is wrong with that? Then I can expect at least 40 minutes of battery life and anything more than that is nice. You will generally not be fully loading the machine so it will always be more than 40 minutes anyway..
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Re:Isn't this simple? (Score:5, Interesting)
No it won't... not all batteries are exactly the same, no matter how good the quality assurance may be, and same goes for the hardware itself, every transistor, capacitor, resistor, transformer, etc all have varying degrees of quality/conduction/capacity.
It could even come down to a single resistor that measures the battery output, could be slightly faulty, and turn the PC off sooner.
They could still say "40 minutes" but it would be more like "32 to 48"... other things come into play as well, such as the temperature/altitude/humidity... how much dust is in/on the heatsinks/vents, or possibly a fault in the charger... the list goes on...
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It could even come down to a single resistor that measures the battery output, could be slightly faulty, and turn the PC off sooner.
Then the laptop is defective and should be sent in for repair/replacement :)
I know that there is some variance ( there always is ) but isn't the metric simply more reliable because of the universal way of testing it ( loading the machine/battery fully ) then some "average" which differs depending on how the manufacturer determines "average"? After all, if you suspend-to-ram, the battery life averages in the tens of hours and on average, that might be the state the laptop is in.
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I'd prefer to see min and max times. Max being light productivity app usage and min being playing a game that utilizes the GPU heavily.
Consumers will see the 2 numbers and can quickly decide if the performance meets their needs based on how they intend to use the laptop. Consumers are smarter than the average monkey. If they see a laptop advertised as "Battery Life: 45 Minutes - 2.5 Hours", they can guess what might affect battery consumption.
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Now try that with every battery off your line, and you have the minimum that you'll advertise. 6 months after selling those machines, the minimum will be even lower because batteries degrade. So maybe you advertise that figure?
And of course, that figure will be something like 10 minutes, which still doesn't give you any kind of an idea of how much time I can reasonably expect my laptop to work off of battery power doing reasonable things.
To be honest, I think they key thing should be that it's standard
Re:Isn't this simple? (Score:5, Insightful)
3) Advertise "minimum" battery life
What is wrong with that? Then I can expect at least 40 minutes of battery life and anything more than that is nice.
What's wrong with that? What's wrong is that you're telling the customer a number that by and large they aren't interested in. What they want to know is if they can watch a full DVD without recharging. If they can work on their Excel spreadsheet for the entire 6-hour cross-country flight if the plane doesn't have plugs. You tell them "minimum 40 minutes" and they say "Whoa! That's not long enough to do anything!" and you say "Well it's just the minimum, under typical usage conditions it will last much longer," and then they ask "And how long is typical? Long enough to watch Casino Royale on BluRay?"
What's your answer? Hypothetically you should be able to actually say whether it'll last long enough to watch the movie, but how do you answer that question in general? What is "typical"? That's what people really want to know, the minimum number doesn't really do them much good except to say that if they really load down the laptop, it won't last long. Which makes the product look bad, and is still by and large not that helpful.
It's not an easy question, more difficult in many ways than talking about performance. Considering that power has only become a major concern for commodity chip makers in recent times, I'm not surprised that their battery life estimates aren't very accurate. Of course, whatever estimate they do use, no matter how accurate, will be measured in a way that makes their parts look good. That won't change, ever. I'm sure that's part of your motivation for the minimum time metric -- there are far fewer ways to screw with it. Which is nice, but not sufficient by itself.
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"Well it's just the minimum, under typical usage conditions it will last much longer"
Incorrect. I would respond, "That is the minimum time under the heaviest possible load it can be put under."
Typical - Hard to pin down because everyone's usage differs for various reasons ( operating system, time of day, intended usage )
Fully loaded - Nearly constant
I'd like to kindly point you to my initial post where I quite clearly said "fully load" and not "typical load"..
Re:Isn't this simple? (Score:4, Insightful)
Incorrect. I would respond, "That is the minimum time under the heaviest possible load it can be put under."
And they'd say "Okay, is playing a DVD the heaviest possible load, so I couldn't even play half of one movie? Or will I be able to play my movie? What about working on my earnings report?" and then you either have to refuse to give them any other number and lose the sale, or start talking about "typical" usage.
I'd like to kindly point you to my initial post where I quite clearly said "fully load" and not "typical load"..
Yes, I noticed, and I'd like to point you to my post where I clearly understood what you are talking about and said "That isn't very useful to the customer". Just because the minimum battery life has the useful property of being easier to quantify without hand-waving and assumptions doesn't mean it's actually the more useful number. Customers want to know if their lap top will last on a cross-country flight doing what it is they usually do.
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Re:Isn't this simple? (Score:5, Insightful)
1) If a customer doesn't know how much load playing a DVD is, they don't care about advertised battery life.
O_o Seriously?
You think knowing the % CPU utilization of watching a DVD (or BluRay, if this makes you feel better) is a pre-requisite to caring about the question "Will my laptop be able to play a full DVD between recharges?"
And I suppose anyone who doesn't know engine timings and torque curves wouldn't care about the question "Can I get to Grandma's house without refueling" too. That's weird, because I care about MPG but know very little about the engine physics that inform it. Should they scrap the "city/highway" MPG usage models, and instead tell you what MPG you'd get with the accelerator floored the entire way?
You're being ridiculous. Obviously people will care about being able to do the things they want to do without knowing exactly how much load on the system that actually entails.
Of course, even if I accept this premise, you're still not giving them the information they want. Okay, so I know that the fully loaded laptop life time is 40 minutes, and I know that my DVD player uses 5% of my processor. Now what? What's the scaling factor so I can do the math? Oh right it's not that easy, even if you're an electrical engineer. I know what it is you said I should know, and you still can't answer the question I care about.
2) Minimum is a more useful number because it always applies. Typical usage figures can be plucked out of thin air because it varies too much.
Easy to figure out is not the same as useful. Minimum is rarely useful because it rarely applies to what the person is actually doing. When the "typical" numbers can be 6x higher than "minimum", and what people really care about is "typical" for all the difficulty of defining what that means, then no minimum isn't that useful.
Sure the minimum should be specified. That does not get you out of the tricky problem of estimating 'typical' battery life, because that is what the customer wants to know, and for good reason. If you refuse to give them anything more useful than minimum, then you lose sales because you can't or won't answer the questions they care about.
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1) Fully load the machine
How? You've got, at a minimum, CPU, GPU, display, and disk. How do you continuously load the CPU so that all execution units are constantly working at their utmost? Same thing with the GPU. As for disk, are you reading, writing, seeking, or switching from one to the other?
Even if you could come up with such a worst-case scheme, it'd probably get so hot that the hardware would either throttle itslf back, or melt.
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What is wrong is that doesn't tell the whole story because it fails to measure real-world performance except for one rare edge-case -- Max CPU duration.
It would be like automobile MPG being estimated based on full-throttle driving on a race track -- it doesn't mirror how the product is actually used. Instead we have city/highway ratings which attempt to mimic two use cases.
The difficulty with automobile engines is that they must operate efficiently across a variety of RPM ranges and trade-offs must be made
Re:Isn't this simple? (Score:4, Insightful)
What is wrong with that?
It gives me, the customer, absolutely nothing to work with. There's a reason we don't calculate "miles per gallon" (or km/l over here) for the "pedal to the metal" case.
In an ideal world (you know, where everyone knows basic math and nobody is fooled by politicians' campaign promises) you'd have a bunch of measurements at various loads and simply print a curve that tells me what I need to know because I have a somewhat good feeling for where my average use scenario is on the curve.
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Re:Isn't this simple? (Score:4, Interesting)
That is a much better and useful idea actually.
Unfortunately, most metrics seemed to be measured with only one value but I would really like to see a 'battery life curve'.
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Is it? To me it is about knowing what I am going to get.
In a choice between knowing I *will* get at least 40 minutes working time or I *might* get the 3 hour "maximum" battery life if I suspend the machine to RAM, I'll take the 40 minutes.
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battery runtime doesn't concern me as much as (Score:5, Informative)
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My experience has been that a new battery that gives 3 hours up uptime gives 2 hours after a year and less than an hour after 3 years. Of course, our laptops are used mostly when docked, so we don't cycle our batteries as often as we could.
Not much different than EPA ratings on cars (Score:4, Insightful)
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on the other hand.. (Score:5, Funny)
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WWJD (Score:2)
Howbout this? (Score:5, Interesting)
I can see more variance in cellphones because those are devices that are on 24 hours on battery and usage patterns are reflective of how many minutes a person has. So someone with 1000 minutes and unlimited sms/data is going to use theirs a lot faster than I, with 550 shared minutes and no data.
On laptops, I think we can get a little more predictability. First of all, I'd venture to say that at least 80% of the time, if the laptop is on battery, it's being used. I don't know of too many people who fire up a laptop and walk off. However the variance is in the type of use. A photoshopper or developer is going to put a lot more stress on the battery than a Word/IE user. A teen is going to stress it more than a octogenarian. And a gamer is going to beat it down more than anyway. Well, maybe not as someone folding@home.
I think the solution for this is for someone with enough clout to develop a standard test that cycles through heavy/light load every 20 minutes. Let it run until it powers off. I think this should be a 'measurement company' such as futuremark. HP/Apple/Dell are never going to agree on a test, but if futuremark creats 'wattmark' and it becomes standard, they'll all use it.
At that point the consumer can say, "Ok, this machine gets 6 hours on wattmark, I'm a LIGHT user, and I usually get 20% more than wattmark" or "I'm a gamer, and I only get half what wattmark says"
But with the vendors publishing their own magic numbers, and consumer has NO idea what THEY can expect out of that machine/battery.
what? (Score:4, Funny)
idle? (Score:2)
This is actually easy to figure out.... (Score:4, Interesting)
Most folks are not going to tap their machines to run 100% on battery, like the 3dmark tests do, but they sure as hell won't leave it sitting idle. So what is the answer? Simple, what DO most folks do while they are on their laptop? Well, from what I have seen that is web browsing, webmail, IM, and document creation/editing.
It really shouldn't be hard to simulate those uses. Since you can get an Open Source app to do each of these jobs you could just build a testing suite consisting of FF3,OO.o, and pidgin and run it, having those apps fed some simulated work(a document fo Writer,a few tabs for FF3, and some basic chat for Pidgin) and see how long the batteries last. I don't know about you but I would rather have a number based on "average Joe" usage than the crap numbers they pushed before or the even more pointless numbers they will be pushing now. Then I would have a real rough estimate of what to expect and could shop accordingly.
Certainly seems like a better way IMHO than some 50/50 split between 3dmark and idle, don't you think?
Give us synthetic and real-world benchmarks (Score:2, Insightful)
Give us "real" numbers like how long the battery will last sitting in a drawer or under "full load" in a particular device, and how long the battery will last under a variety of scenarios.
An "emergency" phone user is more interested in how long they can leave their phone in their glove compartment before recharging.
"Light" users want to know standby time and how many minutes of standby time they lose for every minute they talk.
"Heavy" users are more interested in talk time and how much "talk time" they lose
It's not just batteries (Score:5, Informative)
I wrote a battery driver for a Windows CE device once. Here's how we did that.
There is an A/D line on the AC97 codec that we use as a measurement probe to the battery. Used that to determine the actual voltage being seen. Charged the device 24 hours, and ran a program that dumped that output to a file until it died.
Then fit a third order polynomial to the data. We use that to predict where you're at percentage-wise on the draining curve. Then we made the mistake of looking at the metrics for other batteries we got from the manufacturer.
As it turns out, the characteristics from one battery to the next varied wildly. Even after you average a dozen or so batteries you'd still get better results throwing darts at a dartboard.
In short, that 3DMark06 test is probably reading battery capacity from something similar. That would be worth looking at for another source of possibly bogus readings.
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You may assume that, but there's people out there who are right now wondering how to make a class action case out of this.
Re:Not that big of a deal (Score:4, Funny)
but there's lawyers out there who are right now wondering how to make a class action case out of this.
Fixed that for you ;)
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Can I get a car analogy here? MPG ratings, anyone?
Bueller?
On another note, careful customization of my power profile has allowed my shiny new HP dv4 to be useful for 2+ hours on a single charge. This is with the cheapest 6 cell battery. If I opted for a 12 cell, it would be much longer.
Re:Not that big of a deal (Score:4, Funny)
You naughty boy, you read the article.
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Re:Not that big of a deal (Score:4, Funny)
That's the paradox. Nobody reads the articles, but the slashdot effect is still in full force.
Crazy eh?
FYI, I already read this a few days ago. That's why my comment was funny!
It was just a joke. A goddamned joke. Mother help me.
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Exactly like MPG estimates (Score:5, Insightful)
>>This happens in every industry
This is a bit different from a breakfast cereal saying "now even tastier" or a soap promising "more suds!" The first is subjective (personal preference) but the second is objective -- it can be quantified and proven/disproven.
In this case with batteries, rather than taking an actual measurement of performance, the industry is building an estimate from a combination of measured behavior + a calculation based on a performance variable. It's no different than the automobile industry stating "EPA Estimated MPG city/highway" which is not based on a dynamometer test or actual performance measurement but instead is calculated based on the amount of CO2 which exits the exhaust pipe of the car! Is it any wonder, then, that hybrid cars which shut off their gasoline engine when stopped and at low speed/light acceleration, would give grossly inflated figures? Well, they did (and do), which explains why real-world MPG is often far less than this calculated (not even simulated) performance.
In short, they're both lying and it's obvious. Yet companies wonder why consumers are so cynical and therefore difficult to reach with advertising.
What is needed is real-world testing -- dynamometer ("rolling test track") testing for autos where the wind resistance, temperature, barometric pressure, etc. can all be carefully controlled. Similarly with computers, a pure performance-based measurement is needed which should account for idle time, network activity, etc. Just as an automobile is not tested at full-throttle for 3 hours, neither should a PC, but instead a variety of benchmarks (gaming, web browsing, spreadsheet, word processing, ???) could show performance figures for various activities.
In short, manufacturers, we want real numbers free of hype.
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The problem with fuel economy and battery life measurements is that in the real world you do not drive same as when the vehicle was tested on a dyno.
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It's no different than the automobile industry stating "EPA Estimated MPG city/highway" which is not based on a dynamometer test
EPA tests are done on a dyno: http://www.fueleconomy.org/feg/how_tested.shtml [fueleconomy.org]
or actual performance measurement but instead is calculated based on the amount of CO2 which exits the exhaust pipe of the car! Is it any wonder, then, that hybrid cars which shut off their gasoline engine when stopped and at low speed/light acceleration, would give grossly inflated figures? Well, they did (and do), which explains why real-world MPG is often far less than this calculated (not even simulated) performance.
Why do you think that the testing methodology inflates the estimated mileage for Hybrids because of shut-off's at lights? If your gas engine is shutoff, how much fuel are you burning? Zero. If you are driving a conventional powertrain vehicle and are idling, how much fuel are you burning? Something more than zero. Granted, the crux of the matter is measuring what this something more is, but that's on the conventional side, no
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It's no different than the automobile industry stating "EPA Estimated MPG city/highway" which is not based on a dynamometer test or actual performance measurement but instead is calculated based on the amount of CO2 which exits the exhaust pipe of the car!
I'm sick and tired of hearing this repeated over and over, and even on a website that's supposed to be read by geeky, sciency type people.
Yes, fuel consumption is measured by analyzing exhaust. However, this is an extremely accurate way of measuring it. Calculating the amount of C8H18 required to produce a given quantity of CO2 is a simple problem, one which a high school chemistry student could easily figure out. And it's certainly simpler than ripping apart the fuel system to try and measure every miss
Re:Anonymous Coward (Score:5, Insightful)
No, that's the thing. Everything they've told you is technically true... under certain conditions. Possibly even the conditions that they've listed in a small-print disclaimer (available upon request, if you can arm-wrestle the tiger and win).
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Re:Anonymous Coward (Score:4, Insightful)
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Re:Anonymous Coward (Score:5, Insightful)
"We're Not Entirely Honest" = We've been lying
Actually, "We're Not Entirely Honest" = "We have no idea how to give you an accurate estimate." As someone whose found himself sucked into the battery/mobile power side of a project recently, I can understand why they'd face difficulties.
When it comes to batteries, there are really only three options for measuring how much power is stored: completely drain it over several cycles to see what you get (which is how the manufacturer confirms capacity, but isn't too useful in situ); test the voltage across the terminals and estimate absed on pre-measured battery curves (which is difficult because voltages don't change dramatically until they're nearly drained); or, in some chemistries, measure the temperature changes in the battery (which detects inreactions that don't happen until the battery is almost completely drained). In practice, all you can do is take the manufacturer-specified capacity, derate that based on conditions in your application, and test to see if you came close.
In general, pulling more current from a battery disproportionately decreases remaining capacity. In general, it's pretty difficult to respond to sudden surges and lulls in power consumption for a user's unknown power cycle needs without making your estimate jump all over the place. In general, the problem is just a pain in the neck. It's like ordering a margarita with margarita-flavored ice cubes from a waiter whose never seen you before, then demanding to know exactly how long before you'll need to refill it (regardless of whether you intended to chug it or nurse it).
I'm no expert, but you don't have to be to see it's not a trivial problem.
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Re:Sounds familiar.. (Score:5, Insightful)
If you recall, AMD's performance rating was an important step forward for the CPU manufacturer industry at that time. Intel was pushing for higher and higher clock frequencies with longer and longer pipelines - something that made little sense.
Performance ratings allowed consumers to effectively compare AMD and Intel chips side by side in ways that are useful.
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The problem with laptop battery life is that there isn't really any benchmark available that gives realistic results. No-one turns on a laptop and leaves it idle, and most people don't play games when running on battery. I'd hazard a guess that the most common tasks are browsing the web/email and editing documents.
It shouldn't be hard to come up with a benchmark for those two things. Turn on wifi, load some preset pages in Firefox and repeat every 30 seconds or so. Load up OpenOffice.org, simulate some keyb
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Well, I'm an IT guy and I like facts. I'd personally like to know that I can get "between 45 minutes to 2 hours of battery life, depending on usage," particularly if it's a fairly accurate number.
After all, then I'd know that reading a PDF and/or listening to MP3s might give me around 2.5 and doing heaving dev work w/ an installed Oracle DB and using wireless networking might give me the 45 minutes.
That being said, an average isn't that bad for Joe Sixpack so long as they realize it's an estimate and that
Re:Won't matter soon (Score:4, Insightful)
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