

SSD hard drives tank laptop battery life - dous
http://www.hackaday.com/2008/07/01/ssd-hard-drives-tank-laptop-battery-life/

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pmjordan
Here's the original article instead of the linked meta-babble.

[http://www.tomshardware.com/reviews/ssd-hdd-
battery,1955.htm...](http://www.tomshardware.com/reviews/ssd-hdd-
battery,1955.html)

EDIT: After trying to read and understand the article, I'm beyond confused.
According to the chart on

[http://www.tomshardware.com/reviews/ssd-hdd-
battery,1955-14....](http://www.tomshardware.com/reviews/ssd-hdd-
battery,1955-14.html)

There are two SSDs that consume less power both idle and under load than the
tested HDD. There's no summary data for actual battery life. I think they're
trying to explain the disparity by saying the HDD spends more time idle. I
really can't tell from all the verbose and confusing writing.

~~~
Retric
HDD peek at a higher power level but they can read and write data without
reaching peak power levels when reading and writing sequential data such as
large media files. I don't think this is a big deal as other components swamp
the SSD's power levels and it's not that hard to significantly reduce the
power used in SSD.

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johnyzee
Agreed, the EEE (on which I write this) has surprisingly short battery life
for such a limited device.

However, the SSD more than makes up for the battery consumption by being
silent, blazingly fast and mad robust (this is my four year old son's computer
and he can drop it on the floor while the disk is running without killing it).

I can't wait for SSDs to become standard.

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noonespecial
We use Compact Flash as hdd's is small embedded systems. They are 10x more
battery efficient than a standard laptop hdd and twice as efficient as a
microdrive.

Of course, the largest CF we use is 8 GB and the typical size is 2-4 gb. (I
did my consumption tests on 4GB Sandisks). The smallest used in the article
was 32GB. Perhaps power consumption increases dramatically with size in SSD's?

~~~
wmf
Some of the SSDs in the article are using sophisticated controllers that
consume more power.

------
wallflower
I have an Asus EEE and the battery life is so-so, good enough for a decent
train ride. When I installed software (lots of disk activity) while on
battery, boy the battery went down quick.

~~~
notauser
The old 900:

2 hours battery life.

The new 901:

5 hours battery life.

With the same disk (SSD), battery and screen. The only significant component
change is the processor. If the disk peaks at 2W/4W (SSD/SP) and is mostly
idle then you would really expect it to be lost in the noise of the 20W+ for
the rest of the system.

~~~
wallflower
Argh. Do you have the new 901? That's a big big difference.

~~~
notauser
Not yet, I was going to buy a 900 until I found out about the difference in
battery life.

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silentbicycle
The article seems to contradict itself.

Also, these are still pretty new, and their power efficiency (and prices,
_ahem_ ) will no doubt improve over time.

~~~
ajross
Agreed. There's nothing inherently power-hungry about flash. It's read cycle
looks a lot like DRAM's, but there is no refresh required and the quiescent
power is zero (duh, I guess: that's what non-volatile means).

A flash drive running full tilt and hitting all the cells as fast as possible
is probably going to have power consumption about the same as a DRAM array of
the same size and cycle time, so somewhere in the low-integer watts. If
existing drives are consuming more than that at "idle", then it's pretty
clearly a hardware bug that should be fixed.

------
axod
Surely SSDs would also turn off and enter a power saving mode when not in use?

~~~
mhb
TFA provides enlightenment:

 _In contrast, flash SSDs only seem to know two states: active or idle. We
don’t have specific information on this, but we received confirmation from two
vendors that many flash devices don’t feature power saving mechanisms yet._

