Topic: Flash/SSD drives use as much, if not more, power than standard HD

[nic]

**article copy/pasted to spare everyone the 500 page count filled with add impressions typical from Toms Hardware**

http://www.tomshardware.com/reviews/ssd-hdd-battery,1955.html#

Flash SSDs Don’t Improve Your Notebook Battery Runtime – they Reduce It

Flash-based solid state drives (SSDs) are considered to be the future of performance hard drives http://en.wikipedia.org/wiki/Hard_disk_drive , and everyone seems to be jumping on the bandwagon. We are no exception, as we have been publishing many articles on flash-based SSDs during the last few months, emphasizing the performance gains and the potential power savings brought by flash memory http://en.wikipedia.org/wiki/Flash_memory . And there is nothing wrong with this, since SLC flash SSDs easily outperform conventional hard drives today (SLC = single level cell). However, we have discovered that the power savings aren’t there: in fact, battery runtimes actually decrease if you use a flash SSD.

Could Tom’s Hardware be Wrong?

No, our results are definitely correct. We’ve looked at almost a dozen different flash SSDs from seven vendors over the last few months, and measured acceptable or sometimes even disappointing power requirements with most flash SSDs. In an effort to determine the actual impact on notebook http://en.wikipedia.org/wiki/Notebook systems, we took four SSDs that we had available in our test lab, and ran a series of Mobilemark benchmark runs on a Dell Latitude http://en.wikipedia.org/wiki/Dell_Latitude D630 notebook. We found runtime differences of up to one hour (!) when using a flash SSD compared to a high-performance 7,200 RPM 2.5” notebook hard drive.

Will this Slow Down the Flash Memory Hype?

We don’t think so. Flash is cool, because it’s expensive, and because it does provide significant performance advantages (when SLC flash is used). But while our results are interesting for most users, they will be shocking to road warriors. You will see very clearly in the benchmark section that theory and real life are sometimes entirely different.

We still believe that flash-based drives will be the future for the performance segment, but they must not become a key component for energy-efficient notebooks and ultra-portables — where performance is secondary — as long as their average power consumption http://en.wikipedia.org/wiki/Power_consumption is higher than that of conventional 2.5” notebook hard drives. In fact, even a high-performance 7,200 RPM 2.5” drive provided better overall battery runtime than most of the flash SSDs we put through the Mobilemark test.

How Can Battery Runtime Be Shorter?

It’s important to answer this question, because it doesn’t seem like this should be the case. Most flash SSDs show power requirements in idle and when under load that are comparable to those of conventional 2.5” notebook hard drives. A typical 2.5” hard drive based on rotating magnetic platters usually requires between 0.5 W and 1.3 W when it runs idle, and from 2 W to around 4 W when it is under maximum load. Peak load occurs when the actuator has to move the heads back and forth on the disc surface due to lots of random accesses.

Let me emphasize a part of my last sentence: “when the actuator has to move the heads.” It’s important to understand that a conventional hard drive will only reach its maximum power requirement when you’re requesting random data that’s distributed all over the medium. In the case of sequential reading or writing, hard drives will not require much more than the idle power, as there is no energy-intensive acceleration and deceleration of the actuator.

Flash SSDs Only Know Two Power States

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. On the one hand, the entire industry is looking to improve MLC flash to enable larger flash SSDs at sufficient performance levels. On the other hand, wear leveling algorithms are more important than power saving features, as durability may be an issue with SSD drives.

So while conventional hard drives may operate at relatively low power when little movement is required — such as during sequential read access — flash based drives do not. They will draw their maximum power level constantly when in use, and as a consequence, simply spend more total time drawing maximum power than conventional drives.

More Issues with Ultra-Compact Form Factors Expected

In our comparison, we looked at the difference in battery runtime between four flash SSDs and a 7,200 RPM hard drive, all of which were 2.5” units. Differences between various 2.5” hard drives can be found in the number of platters used — single platter drives are slightly more efficient — and in rotation speed. Drives spinning at 5,400 RPM typically are more energy efficient, while delivering lower performance. In the case of flash SSDs, capacity doesn’t have much of an impact on power consumption: again, there are only idle and active states.

Be Careful With 1.8” Flash SSDs!

However, if we were to take this comparison into the 1.8” space, we can see that conventional hard drives require much less power due to 3,600, 4,200 and soon also 5,400 RPM spindles — typically no more than 2 W. In contrast, the power consumption of flash based SSDs would not change much, because the only significant difference would be the packaging.

According to the experience we had with an initial 1.8” flash SSD, we can say for sure that the power requirements aren’t lower than those of 2.5” flash SSDs. As a result, the flash based SSD will lose the power consumption battle against 1.8” mechanical hard drives.

Flash Performance Developments

While 1.8” flash SSDs will help to raise the performance levels of ultra portables to the same level of compact mainstream business notebooks, most developments can be followed in the 2.5” space.

Performance has improved quite a bit since we received the first flash SSD for review from Samsung. That drive reached a read throughput of 50 MB/s, while delivering less than 30 MB/s in write performance. Today, we are looking at Flash SSDs that deliver way beyond 130 MB/s in read throughput and almost 100 MB/s in writes. All of these drives are based on SLC Flash, and cost $1,000 and up, depending on capacity.

MLC Dominates, But Doesn’t Win

For now, SLC flash is the only option to reach these performance numbers, although MLC is the alternative to achieve higher capacities (due to cost issues), and to move flash based hard drives into the mainstream. All the big flash manufacturers such as Intel focus on MLC flash, because it is cheaper, though not quite as fast as SLC.

Flash SSDs Tested

We looked at four different flash SSDs and added a 2.5” 7,200 RPM conventional hard drive for the sake of comparison. We deliberately selected this hard drive as it delivers high performance and also requires more power than most other drives. If we were to repeat this comparison and use a 5,400 RPM 2.5” drive instead, the flash based SSDs would probably look even worse.

Crucial’s SSD offering is called the CT32GBFAB0, and offers 32 GB or 64 GB of capacity within a 2.5” form factor. As you will see in the benchmarks, this isn’t the fastest flash SSD. Crucial sells the 32 GB version for $749.99 and the 64 GB model for $1,399.99. Both are SATA/150 drives and we found the 32 GB model to be an excellent performer: it reached a read throughput of 124 MB/s, which is even more than what Memoright delivers. However, write performance decreases to less than 60 MB/s, while Memoright maintains an impressive 120 MB/s — of course, the Memoright drives also are clearly more expensive. Crucial failed on us in the PCMark05 application benchmark, where it finished last when the benchmark simulates Windows XP startup.

Crucial provides a five-year warranty for this product, which gives you some comfort when spending so much money. However, the device only reached an average performance score in Mobilemark 07, and after replacing the Hitachi 7K200 7,200 RPM notebook hard drive by the Crucial SDD, our battery runtime decreased from seven hours and three minutes to six hours and three minutes.

Users who purchase this drive because of Crucial’s statements such as “low power consumption” and the product being ideal for “users who want longer battery life” will most likely be disappointed. While the total battery runtime certainly depends on the workload — we used Mobilemark 07 — the minimum and maximum power consumption measurements prove that Crucial’s statements of low power consumption are in fact wrong: 1.6 W idle power is more than any 2.5” notebook hard drive requires.

Memoright MR25.5-032S, 32 GB

The Memoright Flash SSDs have been our favorite flash SSD for some time now. They provide around 120 MB/s of read and write throughput, which bests most other flash based hard drives. Capacities of up to 128 GB are available, though they are ridiculously expensive.

The MR25.5 is based on a SATA/150 interface, which provides a maximum throughput of 126 MB/s. Looking at the performance benchmarks, this is by far the best solution for I/O intensive workloads, as it provides many more I/O operations per second than any other hard drive solution.

This drive also has the highest idle power requirements of all products in this roundup, though, not going below 2 W in idle: as a consequence, we achieved a battery runtime of only six hours and 38 minutes. This is much better than Crucial’s SSD, and Memoright provides significantly more performance as well. Still, you get almost 30 minutes more battery runtime with our Hitachi Travelstar 7K200 hard drive.

Mtron Flash SSD, 32 GB

Mtron is a Korean manufacturer of flash based SSDs and its products have been on the market for a while. We reviewed its 2.5” 32 GB Flash SSD in December 2007, and it is still one of the faster solutions available. This product isn’t an efficiency wonder, as the battery runtime on our test notebook was only six hours and six minutes. This is almost as low as it was with Crucial’s Flash SSD, but the Mtron Flash SSD provides much better write performance, higher I/O operations per second and good Mobilemark 07 performance scores. Again, the mechanical hard drive provides almost one more hour of battery runtime.

Sandisk SSD 5000, 32 GB

We looked at the Sandisk SSD 5000 almost a year ago. It does not belong to the segment of high-speed flash SSDs, as it provides no more than 68 MB/s read throughput and less than 50 MB/s write performance. Still, it is an alternative to some conventional hard drives due to its short access times.

The SSD 5000 is not an I/O operations winner either, as even the Travelstar http://en.wikipedia.org/wiki/Hitachi_Travelstar 7K200 provides more operations per second. And it clearly loses in the Mobilemark 07 performance benchmark, where the Memoright Flash SSD is almost five times faster, and other Flash SSDs provide at least double the performance.

However, the Sandisk http://en.wikipedia.org/wiki/SanDisk SSD 5000 is the only flash based drive that was able to reach the same battery runtime as the conventional Travelstar 7K200 2.5” hard drive by Hitachi: we measured seven hours and two minutes for the Sandisk drive, which is practically identical. So here the claims for power efficiency seem to be true — but there is no improvement in battery runtime over high-performance 2.5” notebook hard drives. Maybe we should have compared this unit to 5,400 RPM drives, but then again the price point and product positioning would be way off.

Reference HDD: Hitachi Travelstar 7K200, 200 GB; 7,200 RPM

Finally, the Travelstar 7K200 is here to defend the reputation of conventional hard drives against charges that they are power hungry, noisy and belong to a dying breed. Of course, there would never be enough flash memory available on the market to replace substantial numbers of conventional hard drive shipments by flash based drives, even if capacity were no issue.

This article shows clearly that the traditional hard drive, which in this case is based on two platters, a 7,200 RPM spindle speed and 8 MB cache, still has every right to exist. These drives will soon reach the 320 GB capacity point, and they offer average users much better battery runtime than most of the flash SSDs that everyone believes to be beneficial for roadrunners, when in fact they’re counterproductive.

Please note that other 7,200 RPM 2.5” notebook hard drives deliver similar results: they beat the flash SSD products when it comes to battery runtime. Read the review on the Hitachi Travelstar 7K200 and 5K250.

Conclusion

The results of our testing are a shock for anyone who cares about battery runtime, as our results prove unmistakably that battery runtimes do not increase when using flash based SSDs. As a matter of fact, most flash SSD products actually contribute to emptying your battery even faster! Mainstream flash SSDs — if they can even be called “mainstream” at prices of $500 and up — do not even provide convincing performance while they help to suck your battery empty quicker than before.

It seems to us that most of the flash SSD vendors never really tried replacing a mechanical drive with one of their flash SSD drives, or they would have found out what we discovered. Instead, most of them are plainly lying by telling the customer about better energy efficiency and potential improvements in battery runtime. I don’t want to point at anyone in particular, as this may have happened because most people aren’t aware of the true facts. Battery runtime may improve if systems run idle, but most of the time they don’t, and this is where the good old hard drive shines brighter than before.

But not all is bad. If you go for one of these highly expensive Flash SSDs by Memoright, you can at least be sure that you get the best drive performance

[africatree]

Often drives will stop working out of nowhere and most people's impulse is to throw them out. Obviously, if the flash gets recognized but wont display its contents, it means it's broken right? Nope! What if you try to write to it but it gives an error and it won't allow reformatting when you try to? Still fixable! Check out this article on recovering broken usb drives for full instructions and software to do it. You'll probably never need to throw out a perfectly good flash drive again. 

[page]

**article copy/pasted to spare everyone the 500 page count filled with add impressions typical from Toms Hardware**

http://www.tomshardware.com/reviews/ssd-hdd-battery,1955.html#

Could Tom’s Hardware be Wrong?

No, our results are definitely correct.

I love confidence. It's not uniquely American, but we've gotten really good at it. 

Thanks for the heads up. When my 722 drive dies, I'd considered getting an SSD, but that puts that thought in jeopardy.

[nic]

bear in mind, the linked article is about 1.5 years old now... maybe newer revisions/models have better power management in their controllers?

[Grey Area]

bear in mind, the linked article is about 1.5 years old now... maybe newer revisions/models have better power management in their controllers?

Not only that, but that article was widely criticized for the testing methodology, and a few weeks later Tom's Hardware had to admit that they had in fact been wrong: http://www.tomshardware.com/reviews/ssd-hard-drive,1968.html

[page]

**article copy/pasted to spare everyone the 500 page count filled with add impressions typical from Toms Hardware**

http://www.tomshardware.com/reviews/ssd-hdd-battery,1955.html#

Could Tom’s Hardware be Wrong?

No, our results are definitely correct.

I love confidence. It's not uniquely American, but we've gotten really good at it. 

Not only that, but that article was widely criticized for the testing methodology, and a few weeks later Tom's Hardware had to admit that they had in fact been wrong: http://www.tomshardware.com/reviews/ssd-hard-drive,1968.html

 

statement stands, it's not uniquely American, but we've gotten good at it.