SSDs save battery power, right? Wrong.
By Joshua Topolsky 
posted July 1st 2008 4:32PM
posted July 1st 2008 4:32PM
[Via Eeeuser; Thanks, Tony]
posted July 1st 2008 4:32PM
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Hard drive tech is much more mature than SSD tech is...if this is still the case in five years, I'll be surprised.
Haha, they just added "JUST READ THE ARTICLE" :O
Using Caps! So BOLD!
I always though engadget posts articles and forgets them, never thought they revisit it to see what their users are saying.
How else would they know when they've the spelling errors?
"On the other hand, you're still getting a drive with no moving parts, which at least makes your data more secure, if not more eco-friendly."
How does "no moving parts" = "eco-friendly"? My monitor has no moving parts and it's not eco-friendly ("but you shoulda seen the moving parts version!")
I think they mean "even though it may not be eco-friendly, ATLEAST it has no moving parts"
Might just be bad wording
This conclusion is biased! I cannot believe anyone would take this seriously! Shame on the people who did made the conclusion! I could take the Sandisk SSD and compare it to four random/crap HDDs in the market. Therefore, I can conclude that SSDs have much better performance and drains much less power.
In order to draw ANY conclusion, you need to test the population, not a sample of 1 versus a sample of 4. Stats 101.
The one-liner conclusion may be biased, but the article does prove the misconception about SSDs being more energy efficient all-around. Your results will naturally vary depending on what drives you test, but the point is that you can't measure energy consumption by idle-power alone -- you have to measure performance-per-watt, and frankly no one has done that until now.
The article doesn't prove anything. The test was flawed. Check the comments of the article.
their tests don't say what they seem to think they say. their test (questionably) shows that the standard hard drive is more efficient under load. that is, when running intensive applications like photoshop, you'll be able to get more done with the same amount of battery with a conventional hard drive (though it might take you longer to do it).
unless you're the type of person to run these sort of applications 100% of the time that your laptop is on and on top of that you're doing this while on battery power, this really doesn't mean very much to you during typical usage.
The Crucial and the Mtron at the end of the list has higher idle power usage, and Joshua already mentioned the gist of it: standard hard drives consume less power because they only hit peak when at load, and more often than not they are at idle.
However, the highest-performing drive on that chart is the Memoright, and at a glance, Tom's Hardware says that nearly all the SSD drives drain more battery than the Hitachi (Except the Sandisk, I think. That drive performs awfully, though). This might be a discrepancy, but note that they used a particular benchmark to simulate heavy laptop use. I suppose the Memoright and the most of the other SSDs hit peak power usage while the Hitachi alternated between idle and load (Going back to what Joshua said).
Theoretically, if you use the laptop for light web browsing, then maybe the SSDs would win out in battery life. That's kind of a sad situation, though. I wouldn't buy an SSD for that.
Ultimately, you'll currently have to swallow the extra battery consumption if you get one of these high-performance SSDs.
Perhaps they'll find a way to fix this in the future.
Actually this article is VERY misleading. Please read the comments on the associated article. Not only is it very poorly written, but their testing methods are not sounds at all.
Pointed out is the fact that SSD's are faster, meaning the computer doesn't sit around waiting on the hard drive as much. The test they used for battery life runs over and over and over as fast as possible and was not focused at stressing the hard drive in particular. This means less time was spent waiting on the hard drive for the SSD and MORE ITERATIONS were completed. This means the CPU, for instance, was in use a LOT more on the SSD. And an active CPU will drain power a lot faster than an active hard drive. The entire test was flawed in execution and the presentation shows it. Yes, their graphs are confusing, because only one of the MANY they throw at you even relates to the battery life. And that one given isn't even an accurate representation of the load on the system.
A far better idea would've been to normalize the result not only by runtime but by how many iterations were completed in each case. Or perhaps use a test that has a constant run time, like DVD playback. Seriously, it's all in the first few pages of the comments to the article if they haven't been deleted.
It just seems to show that some SSDs have awful power consumption. The Sandisk beats the hard drive for both idle and load and thus can't use more energy. And in my view it can only get better.
One question I've never actually seen asked, let alone answered: is there *really* a problem with HD reliability in laptops - or is this a perception thing? Most of the arguments for SSDs are: speed (iffy), low power (well - there goes that one), durability (the debate on real MTBF is still on) and ruggedness (technically, SSD should win this one).
However, there's a tendency to confuse 'potential' with 'reality'. If a product has an MTBF of 100,000 hrs and another with an MTBF of 500,000 hrs.. but it's typical use lifespan is 50,000 hrs - then the two products are essentially *identical* for this application, even though one is technically 5x 'better'.
The average lifespan of a laptop is about 2-3 years but Western Digital warranties their laptop drives for 5 years. One assumes they don't expect a significant number of failures in that time frame (or they'd shorten the warranty). Modern HDs also include advanced shock protection including accelerometers to park the drive head within 2/10th of a second to avoid head/disk collision.
Then there's cost. Yes, SSDs are getting cheaper - but then so are HDs. 320GB for < $200 still trumps 64GB < $250. For the price of 128GB SSD, you can get TWO 320GB HDs and use one just a s straight backup for the internal drive.
So, sorry - the arguments for SSD really just don't stack up. It's neat technology - and yeah, if play pingpong with your laptop (or are a fan of software tricks that do things with the accelerometer, and so constantly slap or shake your laptop, increasing the risk of impact), then SSD is for you.
For the rest of us, HDs just make more sense.
My laptop got about 30 minutes extra battery life because of my ssd, so that's crap...
That's only true if you like to drain your battery unnecessarily by leaving it idle.
I hope you guys refer people to a proper SSD website like dvnation.com
I don't care about their tests, but my battery life increased by 30 minutes from 4:30 to 5:00 when running on lowest performance, 1/7 brightness, and wireless w/ Bluetooth both on; ran a game server to ensure processor was being used and sdd was being accessed. downloaded around 50 GB of files to make sure wireless internet was being used, not just powered on.
I'm happy with this increase; allows me to get through a day without finding a charger or socket.
So far no one has mentioned my favorite part of the article:
"Could Tom’s Hardware be Wrong?
No, our results are definitely correct."
You know I keep seeing this being mentioned and the ting that strikes me as missing in the article at TH is that they do not take into account the increased efficiency of the computer when using SSD all they say is well if we have the same computer run with a hard drive it runs longs, BUT they forget to talk about the fact that when the laptop runs with the SSD it runs 2 - 3 times faster in many of the tests, ergo the CPU uses more power, the North bridge uses More power, the RAM uses more power, the South bridge uses more power and lo and behold the graphics card uses more power all because it can manage to do more calculations. So until they actually stick a Amp meter around the power cords to the hard drive and the SSD drive to see how much power they each pull through the tests I will not believe the crap that is in that article.
Wow, I haven't read Tom's Hardware since about 2000... looks like I haven't missed much.
yes
@Jinnai -
I was convinced by your argument and was going to add on to it until i read the Mobilemark2007 whitepaper. The modules ran during the battery life test DID level the amount of work done per unit of time under both SSD and HDD systems.
There are 3 modules TH could have used to test this (DVD, Reader, and Productivity). The DVD module will run the same video (work) per unit time. The same is true for the Reader module, which simulates 1 page turn every 2 minutes. For the Productivity module:
“The Productivity module is somewhat more complex. One cycle of this workload is completed every two hours. There is a fixed amount of work that takes place within that period of time, with the balance of the time taken by fixed-length and variable-length user delays distributed throughout the workload to simulate user “away” or “think” time. The variable-length pauses ensure that a faster system and a slower system will do the same amount of work in a given amount of time. This two-hour cycle is repeated until the battery is depleted.”
However, I am still not convinced by TH's article. I anxiously await more articles that will either debunk this one or add to its credibility.
Actually, the white paper says it has modules that do load balance, but those weren't the ones used for some reason. From page 3 of the comments on the article itself I quote mastrom:
"Going to http://www.bapco.com/techdocs.html I found the white paper for Mobilemark 2007. Under paragraph 2.5.2 Battery life rating methodology I read: "The benchmark generates battery life ratings as its principal metric. The battery life rating in MobileMark 2007 is measured in minutes. This metric reflects the number of minutes the system can remain operational while executing a chosen module. Each module will produce a different battery life rating, reflecting differences in system loading."
Everything ok until now. Each module should accommodate different usage patterns. And it continues: "The battery life is established by recording the start time of the benchmark, then repeatedly performing the workload. When the remaining battery capacity has fallen to 7% the benchmark records a timestamp once per minute. Once the battery has been depleted and the computer plugged in and rebooted, the benchmark compares the “start” timestamp and last recorded (“end”) timestamp. The battery life rating is the number of minutes between these timestamps."
Did you notice the important detail? "REPEATEDLY performing the workload". Well my friend, this is the reason your conclusion is completely off base. It is proved and accepted the SSD drives are faster (on average) than conventional Hard Disk Drives. Even your graphs prove this fact. However when you test the battery life by repeating the same workload again and again you force the system to perform more cycles of the same workload when the SSD is used compared to the HDD because most tasks in the workload wait for the hard disk to finish a task to move to the next. So unless you tell us how many times the workload was repeated by each configuration you can't compare the battery life times...
That’s is why the DVD playback test is so popular in battery life tests. It makes sure the computer will perform the same work per x amount of time. So please explain to me why you didn't publish the results of the "DVD2007: Battery Life" and the "Reader 2007: Battery Life" modules which are part of the MobileMark2007 as I see at the paragraph "3.0 MobileMark 2007 Scoring Methodology" in the white paper."
Interesting, I read that part differently. When I read "repeatedly performing the workload," I assumed it was a balanced or time-leveled workload, given the section I posted above. I did not take it to mean that the system would perform the workload at maximum capacity and repeat an indefinite number of times. Hopefully someone will be able to clarify this.
I also wish that TH would post the scores for the 3 separate modules though.
I totally disagree with the Tom's Hardware findings. At LAPTOP, we ran a test with an Eee PC 1000H where we took its 5,400 rpm hard drive out and put in a Samsung SATA II 64GB SSD. The result? 20 more minutes of battery life.
http://blog.laptopmag.com/eee-pc-1000h-faster-with-ssd-upgrade
"then my work is done"
gee... that snide reply REALLY makes me want to visit your spam site now!
if ssd indeed trains ur juice faster, then why no one ever complained about it before, no body brought a ssd yet?
1) noone can deny the advantage of faster bootup/performance. This test does not account for increased performance, just endless cycling.
2) In the real world isn't there more idle time?
TH fails again.
Regardless of the power state, give them time, Id rather have a drive thats is just a wiiii bit more power hungry if it has no mechanical parts. But I disagree with the tests on its relavence to the SSD themselves, esp. Tom's tests. Hopefully better tests will spring up.
and hopefully Engadget will take away that yelling text on the image of the article. I hate being yelled at for no reason.
good thing i decided long ago to hold out for the 320 gb ssd..by then they should sort this out!
Interesting. But I'm not convinced this test represents a real-world scenario very well.
Mischa Lockton ALMOST got it right. As mentioned, SSDs are faster. ...This means they get more done in less time. So, let's presume Tom is right and eb else is wrong, that SSDs use slightly more power than a HDD. They still probably use less power to get the job done because they take less time to do the job.
If an SSD uses a little more juice but takes a little less time to get the job done it still saves battery life. Also remember that while the clock is running on the traditional HDD you're wasting CPU+Cell+WIFI, etc.
the power savings was never substantial enough to be a buying consideration for me. it's all about reliability and performance. ever tried using a laptop on a bumpy road? ...ever had a HDD crash with important data because airport security in Charlotte, NC dropped it? it sucks.