Wednesday, July 2nd 2008

SSDs Don't Reduce Power-consumption, they Increase it

And you thought your solid-state hard-drive (SSD) increased your laptop's battery life? Think again. In a new article, Tom's Hardware investigated the possibility that SSDs in fact increase power consumption of the system, and the results were astonishing.

While a conventional hard-drive idles at 0.5W to 1.3W, it's only during heavy-duty as in lots of random-access, when the actuator moves the heads back and forth that the drive could peak at up to 4W. NAND Flash based SSDs only know two power states, 'idle' and 'active', SSDs from some vendors don't even feature these. While power consumption of conventional drives are proportional to their form-factor since it affects the weight of the platter(s) and effectively the load on the motor, with SSDs, form factor doesn't affect consumption, and a 1.8" SSD could have higher idle consumption than its conventional counterpart.

You can read the article here.


Source: Tom's Hardware
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15 Comments on SSDs Don't Reduce Power-consumption, they Increase it

#1
PVTCaboose1337
Graphical Hacker
That kinda kills off the marketing!
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#2
WhiteLotus
I think they will get around to this some time soon. And for desktop users - it's not going to bother them.
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#3
lemonadesoda
Interesting stuff.

But I dont agree with the analysis. They used "mobilemark" as the denominator in their statistics... which is completely arbitrary.

IMO this is the relevant chart:



If your laptop/PC is sitting there inactive at the desktop, then you WILL get a lot more battery life with the Sandisk and Memoright.

But if you have a Mtron, your laptop battery will not last as long.

BUT

If you consider the #data transactions / power then SSD wins. You battery might not last as long... but in the time you've got... you will get a lot more done, even with the Mtron.
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#4
csendesmark
Personally, I dont care with power consumption, if the difference not bigger than 30~40%
And the SSDs acess time "is ~0ms" , transfer rate is bigger too
Posted on Reply
#5
Katanai
Yeah I've smelled something fishy about this when I've seen first tests and the actual power usage of SSD's were almost equal with HDD's. I was like first you're telling me that they draw less power, now tests prove they draw the same, what's next? Well I guess this is it. It's still unproven technology though. They draw more power because they have a lot of chips. Maybe in the future they will only need one or two. Then they will work as first advertised, like many products do...
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#6
chron
You're giving up battery life, sure, but you're also gaining productivity. It's hard to measure how much time you save from simply not waiting on a hdd. I'm sure it's no 30 hours per battery rechard (lol) but still, that's something to consider.
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#7
btarunr
Editor & Senior Moderator
A computer hard drive spends more time idle than seeking data. SSDs aren't very battery friendly when idle.
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#8
jtleon
I'd say that MobileMark07 chart is a legit comparison. What else is out there to perform this test?

Consider that a spinning disk should use very little power to keep spinning - the biggest power is required to spin up the disk from a power down condition. The seek head motion is a tiny part of the drive power consumption.

However - the flash chips use the same off-on power each time data is accessed - The entire 32GB of chips must energize when seeking - as the array has no idea where data shall be retrieved. Although the power to energize the array may be significantly less than the spin up power of a disc - the number of these chip array power cycles is probably 1,000,000X greater during this benchmark test. Pls advise if this logic is incorrect.

This MobileMark test clearly indicates the SSD technology is still in its infancy!
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#9
mlupple
I'll take performance over carbon footprint any day.
Posted on Reply
#10
btarunr
Editor & Senior Moderator
by: mlupple
I'll take performance over carbon footprint any day.
It's not a question of eco-friendliness, but of your laptop battery running out before it should.
Posted on Reply
#11
mlupple
That's why I don't own a laptop. The batteries are shit. If I need to check my email there's a computer anywhere I go. Or my phone.
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#12
OnBoard
Not that surprising considering how long there have been laptop HDDs compared to SSDs. Still you get (hopefully) less heat/noise and more performance. No-one is forcing you to buy the power thirsty one, get the best in the test and it will surely beat a couple years old current laptop drive.

Another thing not to buy before reading reviews / user input :)
Posted on Reply
#13
Hayder_Master
ssd, it's future and time of old hard drive become very short, old hard drive it is only the problem which keep pc slow, cuz it is only physical part in case (keep cd-drive out cuz we talk about performance) , ssd drive it is the revolution of technology which make pc without problems.
Posted on Reply
#14
Mussels
Moderprator
well thats interesting.

obviously, SSD's are there for noise and speed, not power saving.

That said... did they test the say, 8GB models in the macbook air? i'm sure this varies a lot between types of SSD's.

(as an example for how this could be flawed: if i was watching a movie, the SSD would load it a lot faster and therefore be on less often. it would spend more time in the idle state, so this problem could in fact not exist in the real world)
Posted on Reply
#15
R-T-B
by: csendesmark
Personally, I dont care with power consumption, if the difference not bigger than 30~40%
And the SSDs acess time "is ~0ms" , transfer rate is bigger too
Actually the transfer rate on many SSDs is lower. It's the access time that is amazing, HD's can keep up pretty well when it comes to burst sequential data.
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