The SSD Relapse: Understanding and Choosing the Best SSD
by Anand Lal Shimpi on August 30, 2009 12:00 AM EST- Posted in
- Storage
Power Consumption
SSDs are at their highest power consumption when performing large file sequential writes. The majority of the power consumption comes from writing to the NAND flash and when you’re doing sequential writes you have more flash devices engaged at a time. Thus my peak power consumption test involves measuring power used over the 5V rail while the drives perform my 2MB sequential write benchmark in Iometer and at idle of course.
First, the idle numbers:
The Samsung and Indilinx drives use the least power, while the Intel drives use the most out of the SSDs. Intel honestly just needs to stick some power gate transistors in front of the controller and flash to curb power consumption at idle. They are all still lower than a mechanical drive, and much lower than a 3.5" HDD.
It's also worth noting that given the order of magnitude performance advantage these drives hold over traditional hard drives, they spend far more time at idle than their mechanical counterparts.
Under load the SSDs use anywhere from 2.5 - 3.5W, the exception being the Indilinx SLC drive which comes in at under 2W. Power consumption is roughly half if you switch to a random write workload, and the standings also switch places. While Intel's X25-M G2 draws less power than the OCZ Vertex Turbo in the sequential write test, it draws more power in a random write workload:
| Random Write Power Consumption | Min | Average | Max |
| Intel X25-M G2 160GB (MLC) | 1.55 W | 1.60 W | 1.7 W |
| OCZ Vertex Turbo 128GB (Indilinx MLC) | 1.13 W | 1.17 W | 1.21 W |
As I alluded to before, the much higher performance of these drives than a traditional hard drive means that they spend much more time at an idle power state. The Seagate Momentus 5400.6 has roughly the same power characteristics of these two drives, but they outperform the Seagate by a factor of at least 16x. In other words, a good SSD delivers an order of magnitude better performance per watt than even a very efficient hard drive.
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Anand Lal Shimpi - Monday, August 31, 2009 - link
Intel insists it's not an artificial cap and I tend to believe the source that fed me that information.That being said, if it's not an artificial cap it's either:
1) Designed that way and can't be changed without a new controller
2) A bug and can be fixed with firmware
3) A bug and can't be fixed without a new controller
Or some combination of those items. We'll see :)
Take care,
Anand
Adul - Monday, August 31, 2009 - link
Another fine article anand :). Keep up the good work.CurseTheSky - Monday, August 31, 2009 - link
This is absolutely the best article I've read in a very long time - not just from Anandtech - from anywhere.I've been collecting information and comparing benchmarks / testimonials for over a month, trying to help myself decide between Intel, Indilinx, and Samsung-based drives. While it was easy to see that one of the three trails the pack, it was difficult to decide if the Intel G2 or Indilinx drives were the best bang for the buck.
This article made it all apparent: The Intel G2 drives have better random read / write performance, but worse sequential write performance. Regardless, both drives are perfectly acceptable for every day use, and the real world difference would be hardly noticeable. Now if only the Intel drives would come back in stock, close to MSRP.
Thank you for taking the time to write the article.
deputc26 - Monday, August 31, 2009 - link
been waiting months for this one.therealnickdanger - Monday, August 31, 2009 - link
Ditto! Thanks Anand! Now the big question... Intel G2 or Vertex Turbo? :) It's nice to have options!Hank Scorpion - Monday, August 31, 2009 - link
Anand,YOU ARE A LEGEND!!! go and get some good sleep, thanks for answering and allaying my fears... i appreciate all your hard work!!!!
256GB OCZ Vertex is on the top of my list as soon as a validated Windows 7 TRIM firmware that doesnt need any work by me is organized....
once a firmware is organised then my new machine is born.... MUHAHAHAHAHAHA
AbRASiON - Monday, August 31, 2009 - link
Vertex Turbo is a complete rip off, Anand clearly held back saying it from offending the guy at OCZ.Now the other OCZ models however, could be a different story.
MikeZZZZ - Monday, August 31, 2009 - link
I too love my Vertex. Running these things in RAID0 will blow your mind. I'm just waiting for some affordable enterprise-class drives for our servers.Mike
http://solidstatedrivehome.com">http://solidstatedrivehome.com
JPS - Monday, August 31, 2009 - link
I loved the first draft of the Anthology and this is a great follow-up. I have been running a Vertex in workstation and laptop for months know and continue to be amazed at the difference when I boot up a comparable system still running standard HDDs.gigahertz20 - Monday, August 31, 2009 - link
Another great article from Anand, now where can I get my Intel X-25M G2 :)