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AMD — "We're Not Entirely Honest" About Batteries
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."
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..
The disappearing pencil trick. Let me show you it.
battery lifetime. I maintain about 200 laptops, and the damn batteries are usually completely useless after about a year. Oh, and of course, the laptop has a 3 year warranty, and the batteries have 1 year warranties. You can extend that to two years -- it'll only cost you about as much as a second battery would to do so.
I am not left-handed, either!
..at least they're being honest about not being entirely honest..
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).
The World Wide Web is dying. Soon, we shall have only the Internet.
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.
You can't legislate goodness. Let each to his own destiny, by will of his freely made choices.
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.
Do not meddle in the affairs of sysadmins, for they are subtle, and quick to anger.
I'm shocked! SHOCKED I tell you! You mean the phones/laptops don't run as long as advertised? I can't believe this! It's impossible! Next you'll tell me a 8GB pendrive/SSD holds less than 2^33 bytes.
>>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.
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.
Weaselmancer
rediculous.
"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.