[sclug] Under(re)volting - How does MS do it?

Goten Xiao goten at squad-wars.com
Thu Mar 1 09:23:59 UTC 2007


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alan c wrote:
> Pieter Claassen wrote:
>> Hi Guys, I just got a brand new lenovo X60s from the Uni (which I
>> am now
>> regretting because it works so badly with Linux).
>>
>> Many things don't work (most notably switching between external VGA
>> and
>> the laptop screen, increasing screen brightness, disabling wireless
>> and
>> bluetooth etc.).
>>
>> But, what is really worrying is that the battery barely lasts 2
>> hours on
>> this thing, even with dual cores (Intel Dual Core 1.66GHz with 2400MB
>> Cache). The cpufreq governor works fine for both cpu's but only has
>> three steps (1,1.33 and 1.66 GHz).
>>
>> So, the question is simply: How come Microsoft manages to get around 6
>> hours out of this battery (urban legend) while the best I can do
>> (after
>> manually disabling wireless, unloading USB drivers, enabling laptop
>> mode) is only 2 hours? Yes, I know P=V^2/R which I suspect that even a
>> minor drop in board voltage will have significant power gains.
>> However,
>> everything I read warns me against patching the kernel for
>> undervolting
>> because of possible hardware damage (motherboard not chip).
>>
>> So, how is Microsoft doing this? How can I do this?
>>
>> Oh, I am on Ubuntu Feisty.
>
> My guesses would include control of processsor speed at least.
> Are you able to get 6 hours *yourself* using windows? or is the 6
> hours a marketing myth? Batteries also are notorious for having
> difficult to define capacity.
My ancient Dell Latitude CPxJ650 (or whatever the model number is)
suffers from chronic memory effect; ten minutes after using it it
claims it has 15 minutes of battery life remaining.
Have you tried setting the suspend time on your hard drive? You should
be able to cut down a significant portion of energy use with that.
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