Solid State Drives (SSD) Reduce Battery Life?

[MacRumors]

Tom's Hardware publishes some interesting conclusions based on their testing of Solid State Drives (SSD) in laptops. They report that contrary to popular belief, SSD drives actually reduce the battery life in laptops as compared to traditional Hard Disk Drives (HDD). They try to explain this difference by theorizing that traditional hard drives rarely reach peak power consumption and are typically in a low power state. SSDs, however, are only "active or idle" without any additional power saving mechanisms.

Tom's Hardware seems confident in their results and compared four different Flash SSD drives to a traditional hard drive. The results either showed no change in battery life or up to one hour (14%) less battery life for the test system (Dell Latitude D630). Testing was performed using the MobileMark 2007 benchmark which specifically measures battery life performance under "real world" usage. Despite the worse battery times, the SSD drives did outperform the traditional hard drive by a significant margin.

The only Mac which currently ships with a Solid State Drive option is the MacBook Air. Battery benchmarks for the MacBook Air showed modest gains vs no gains depending on the reviewer. It has been widely expected that Solid State Drives will become more available as prices on Flash memory drops. Besides improvements in performance, SSDs are also believed to be less prone to data loss.

Article Link

 

[gkarris]

New technology - the power consumption on SSD's should go down.

They are a lot faster as far as access. When I'm at the Apple Store I like using the MacBook Airs with the SSD drives - nice 'n fast.

 

[decimortis]

New technology - the power consumption on SSD's should go down.

They are a lot faster as far as access. When I'm at the Apple Store I like using the MacBook Airs with the SSD drives - nice 'n fast.

Agreed.

One step back to take 3 forward has to happen sometimes.

 

[cwingrav]

Extra OS costs too?

I might be missing something but there should be extra overhead in the OS to maximize the hard drive's speed. For instance, constantly moving bits around and such so data is local. That should require OS changes to improve the life of these things.

Anyone who tinkers in such things care to comment?

BTW.. I will now read the article and see if something was said about this. Got things in reverse order.

 

[amusiccale]

Well, people really worried about battery life might spring for a laptop with a user-replaceable battery. I think the stability is the better selling point and that power consumption will eventually drop over time.

 

[gonnabuyamac]

I think since SSD is such a new technology for laptops, we still have a ways to go before we really see them honed to get all of their potential. I hope it's not too long though. I'd love to retire this MBP in a few years for a super cool MBP with an SSD.

 

[iSee]

It seems like the MBA SSD is a high-quality drive since it is slightly better to even in power consumption vs. the 1.8" HD option.

Tom's Hardware points out that none of the SSDs they tested would match or beat a 1.8" "normal" hard drive, so it's impressive that Apple's does...

... or maybe the MBA's standard 1.8" hard drive is a power hog!

 

[digitalbiker]

Personally I am waiting for the next update to MBA. Hopefully it will use newer larger SSD drives and also improve the OS to optimize the drive for battery life.

The performance boost is the most important thing to me. Using the MBA with SSD in the Apple Store, compared to the slow HDD versions makes a big difference.

You really notice the almost instant on speed of the MBA SSD and the very quick launch of apps for the first time. Some apps take 3 or 4 times longer to load when initially launched.

It would be extremely nice if Apple offered a 15" version of the MBA, with more ram, more storage, bigger battery, and Wi-Max card.

 

[cwingrav]

Ok, read article. Looks like the conclusions don't match the test. First off, this was all done on a windows box so the conclusions won't be cross OS applicable. Interesting all the same.

Are there some projects working to write better SSD drivers? A lot of the algorithms that optimize the OS for HDs cause problems for SSDs. I did some searches for Linux but didn't see anything. I know OSX does a lot to constantly move bits of applications and data around to optimize speed. I'm sure they are looking forward to cutting out that bloat from their OS (and a few OS tinkers going 'darn, i worked hard on that').

Clarify my point------
Basically, by moving bits around to make them easier to read for the HD, this is extra work/power for the SSD that has no impact of performance.

 

[pjac]

I haven't read the article to double check, but I've heard it suggested that Tom's hardware messed up in a sublte way: They seem to have set the machines running on some looped task, and timed how long the battery lasts.

They don't mention how much work the computer did - perhaps the bettery was just used up sooner with a SSD because an IO bottle neck was removed, allowing the CPU to do more work (and use up the battery faster).

 

[Zwhaler]

Given that SSDs are way faster than HDD, maybe manufacturers can focus on making them less power hungry as opposed to high density for the time being. Unless no one cares, which I think might be the case.

 

[~Shard~]

Personally I am waiting for the next update to MBA. Hopefully it will use newer larger SSD drives and also improve the OS to optimize the drive for battery life.

And don't forget at a lower cost as well.

As others have stated, I'm sure once the use of this technology becomes more commonplace we will see efficiency improvements.

 

[nagromme]

Interesting. I wonder if there are cases where the heat of an HD makes the fans run more?

I still want no moving parts, when the cost comes down.

 

[rezonat0r]

This was already posted and ripped to shreds on Slashdot. Read the comments.

http://hardware.slashdot.org/article.pl?sid=08/07/02/134256

 

[err404]

For the record the test performed at by TH had a critical flaw.
The test was simply ran continuously until the battery was dead. Since the SSD is significantly faster then a traditional HDD, more iterations of the test may have been completed. In terms of "work" done in by each drive, the SSD may have moved more bits of data during the same time.

It's like testing the MPG of two cars w/o considering the speed of each vehicle.

I would like to see the tests re-run with comparable work loads for both drives.

 

[NightGeometry]

I haven't read the article to double check, but I've heard it suggested that Tom's hardware messed up in a sublte way: They seem to have set the machines running on some looped task, and timed how long the battery lasts.

They don't mention how much work the computer did - perhaps the bettery was just used up sooner with a SSD because an IO bottle neck was removed, allowing the CPU to do more work (and use up the battery faster).

The other problem is that with an HDD spinning constantly it is reasonably efficient, the problem is with spin up, against an SSD's 'instant on'. So constant data read / write you may expect an HDD to be as or more efficient than an SSD (barring I/O bottlenecks caused during the test), but for intermittent read / writes requiring random access the SSD should absolutely trash the HDD, even without any OS level optimisation.

If you can open a movie and load it into memory completely, and do nothing else except watch the movie, and your OS doesn't swap anything out, then you should expect to see similar battery life with either HDD or SSD. If you are constantly writing data to disk, HDD should be better, if you are doing occasional read / writes then the SSD should be better. The test run was constant read / writes.

A good example was a task that reads from disk one second in every ten. Repeat this test over one minute and the SSD will go to 'read power' for a total of 6 seconds (lets give some margin and say 12, which is hugely exaggerating), an HDD will most likely be spinned up ('read power') for a full minute. This is not so unusual an example of disk usage.

Slashdot is covering this - there are some very good examples of just how bad the test methodology is, plus some interesting ways a better test may be run.

Personally - I prefer HDD's for now for other reasons (cost and better understood MTBF).

 

[wizard]

Wrong OS to test on!

If they really want to test SSD they really need to use an OS that is optimized to some extent for SSD. The only one that comes close right now is Linux. Most current OS'es have their disk I/O systems set up to work with the latencies seen in rotating media.

The other issue that might invalidate this study is that due to SSD being faster for some operations the CPU can be spending less time spinning its wheels. I have to wonder if they got more work out of the PC with the SSD.

It is nice that people are testing such issues, but I'd fell much better if they simply tested raw power consumed by the storage devices. Sure a lot harder to do without the right equipment but it would remove a lot of variables.

Dave

 

[137489]

Ok, read article. Looks like the conclusions don't match the test. First off, this was all done on a windows box so the conclusions won't be cross OS applicable. Interesting all the same.

Are there some projects working to write better SSD drivers? A lot of the algorithms that optimize the OS for HDs cause problems for SSDs. I did some searches for Linux but didn't see anything. I know OSX does a lot to constantly move bits of applications and data around to optimize speed. I'm sure they are looking forward to cutting out that bloat from their OS (and a few OS tinkers going 'darn, i worked hard on that').

Clarify my point------
Basically, by moving bits around to make them easier to read for the HD, this is extra work/power for the SSD that has no impact of performance.

This article sounds interesting, but like you I am confused.

When I look at my mac, my applications are 1 file and rather large (ok, mac apps are small and compact - but there are some apps I have that are large).

When I look at my Windows PC, my applications are made up of a bunch of DLL's and registries that could be in different directories (ie some even store in the \Windows\system32 folder which I hate as that is an OS reserved folder).

I can see where a Windows box may have issues as the pieces to run an app are strewn all over the place, and they does not even count for file fragmentation. Also, if they are anything like jump drives, data loss can be an issue. I had a file that was fine on one PC, but when I plugged the jump drive into another PC the file got corrupted. Ok, there are harddrives so I know we won't be swapping them that much - but still brings the point that things can get corrupted no mater what technology. But yes, I had data loss in my early days because someone bumped a table while my harddrive was writing data and the heads skipped.

Never the less, the biggest issues to me is the hard-drive speed, CPU speed, RAM, battery life, and cost. Large files take forever to load, so if I could get away from spinning fragmented platters - would be nice. I am far off from buying another laptop (my Dell I use as a backup for work is barely hanging on, and i just bought a macbook in April), but in a few years when I am ready for an upgrade - It would be nice if I could get a nice macbook with a 300gb SDD at a reasonable price.

I would still like to know what makes a common HD in a mac quieter than in a PC? being a switcher, i am used to looking at flashing lights or listen to the hard drive chatter to see if the PC was doing something. Now, if I am waiting on a large file, I am like "ok this thing running?"

Although I do love the quietness, listening to my wife's 2 year old desk top chattering away when it is idle can be annoying.

 

[David G.]

I love how the buyers guide links are for the MacBook and the MacBook Pro but not for the MacBook Air.

 

[mdriftmeyer]

New technology - the power consumption on SSD's should go down.

They are a lot faster as far as access. When I'm at the Apple Store I like using the MacBook Airs with the SSD drives - nice 'n fast.

It's not new technology. It's a new application of old technology.

We have plenty of experience to reduce power for Solid State drives. We have motherboards, CPUs and other IC designs to leverage long before they applied this to the hard drive paradigm.

 

[JQW]

This article sounds interesting, but like you I am confused.

When I look at my mac, my applications are 1 file and rather large (ok, mac apps are small and compact - but there are some apps I have that are large).

When I look at my Windows PC, my applications are made up of a bunch of DLL's and registries that could be in different directories (ie some even store in the \Windows\system32 folder which I hate as that is an OS reserved folder).

No, that's wrong.

Mac applications may appear under the Finder as being a single file, but the truth is that they are really directories containing many files. Inside this directory as well as there being the binary file that comprised the main application, there's can also be dynamic library files (the equivalent to Windows DLLs) and other applications that the main one may use. There directory structure will also contain other resources such as help files, international language support, graphic files, sound files and anything else the particular application may need.

As well as that there's other shared libraries scattered around the Mac OS X disk. Many of the core ones are in places like /usr/lib and invisible to finder. Others are hidden inside Frameworks in /System/Library/Frameworks.

 

[lowbatteries]

It's like testing the MPG of two cars w/o considering the speed of each vehicle.

Speed wouldn't make a difference in testing for miles per gallon. I think the analogy you were going for was having two cars drive around until their tank runs out, without factoring in how many miles they went.

The computers with SSD (possibly) went more miles, so their tanks ran out faster.

 

[mdriftmeyer]

If they really want to test SSD they really need to use an OS that is optimized to some extent for SSD. The only one that comes close right now is Linux. Most current OS'es have their disk I/O systems set up to work with the latencies seen in rotating media.

The other issue that might invalidate this study is that due to SSD being faster for some operations the CPU can be spending less time spinning its wheels. I have to wonder if they got more work out of the PC with the SSD.

It is nice that people are testing such issues, but I'd fell much better if they simply tested raw power consumed by the storage devices. Sure a lot harder to do without the right equipment but it would remove a lot of variables.

Dave

You won't be getting more work done, just getting processes to complete in shorter time frames. Unless we're dealing with a fully automated control system environment the amount of work done is directly dependent upon the operator.

 

[cwingrav]

Speed wouldn't make a difference in testing for miles per gallon. I think the analogy you were going for was having two cars drive around until their tank runs out, without factoring in how many miles they went.

The computers with SSD (possibly) went more miles, so their tanks ran out faster.

But that would only be true if driving around in a vacuum to avoid wind resistance. The first post was correct in a round about way. Unfortunately, that test had to cease after all ten test cars failed to get more then 2 tenths of a mile before the drivers suffocated.

 

[alphaod]

I recently bought a SSD for my tablet computer and my battery life improved by 25% and my boot/shutdown times decreased by 75%, so I don't care for Tom's Hardware results; all I know is my performance and battery improved.