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Second-Generation SandForce: It's All About Compression

OCZ's Vertex 3: Second-Generation SandForce For The Masses
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After explaining the differences, it might surprise you to learn how much SandForce's second generation logic is similar from it replaces. In our Vertex 3 Pro preview, we explained the changes in these new controllers:

  1. Better Performance. We now have native SATA 6Gb/s (excluding SF-21xx).
  2. Updated support of toggle-mode and ONFi 2.2
  3. Security gets a notable boost from AES-256 (up from 128-bit encryption previously).
  4. Better Error Correction Code.
  5. Power throttling.

Much of the magic in a SandForce-based drive comes from data compression. When you write a large Word document to the drive, it's easy for the controller to compress (in comparison, a ZIP file is already compressed, and consequently cannot be easily made smaller). Your computer still thinks that a 3 MB doc file is being written as 3 MB, but once that data hits the controller, it ideally ends up as 1.5 MB. This compression helps lower write amplification and extend the life of the drive by using fewer program-erase cycles.

If the controller is compressing data, you might wonder why a SandForce-based drive can’t just double its storage capacity. Say you have a 120 GB Vertex 2. If you filled up the drive with 50 GB of compressible data squished down into 25 GB of written information, where does the other 25 GB go? Well, it is added to the pool of overprovisioning. There is no way to use this as additional storage space because of the way an OS addresses LBA space. Operating systems recognize a static, not a dynamic, LBA. From a stability standpoint, you don’t want the address of recently-written data to keep changing. However, there is a tangible benefit to compression besides writing less. Remember, more overprovisioning means less data has to be moved around as the drive is filled. This means you could actually get the benefit of enterprise level provisioning (28%) if you were writing easily-compressible data.

The key here is what happens when you transition over to a wider bus interface. Compression has to occur faster. If you're moving data at up to 500 MB/s, the controller's processor works harder to move information through that larger pipe. The controller itself is more like a rail yard conductor, pulling switches to divert traffic. This switching mechanism is handled by the circuit's CPU, but the amount of switching really hasn't changed. This is why all SandForce controllers use the same Tensilica DC_570T processor. The compression engine is what changes. All second-generation controllers feature a bigger block of silicon dedicated to DuraWrite, the technology SandForce cites as being responsible for compression. Likewise, the recycler and garbage collection algorithms have been upgraded because the controller can only write as fast as it can clean once blocks need to be reused.

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  • 0 Hide
    lradunovic77 , February 24, 2011 12:41 PM
    SSD prices are really down slow and that is because HDD is still selling.
  • -4 Hide
    lradunovic77 , February 24, 2011 1:17 PM
    I agree and it is time for HDD to be retired. We don't need them anymore, but Servers.
  • 3 Hide
    bildo123 , February 24, 2011 1:18 PM
    A far cry as far as "the masses" are concerned. Still, over $2/GB is too much. Getting closer however. I'd pay $200 for a 256GB SSD with these speeds.
  • 0 Hide
    lradunovic77 , February 24, 2011 1:19 PM
    I am sure price will really drop by end of this year.
  • 0 Hide
    acku , February 24, 2011 1:20 PM
    mayankleoboy1the fact that they use ~15% of a quad core SB CPU, is amazing.with the mechanical drives, they were just sitting idle. this more than anything, makes the SSD worthwhile.


    Well what I didn't mention in the review is that the benchmark starts as ~20% across all cores during the first 10 seconds, which is from PCMark setting up the disk trace. After that, the IO activity throttles a single core up to 100% for almost all SSDs. For the hard drives, we see ~60-80% utilization of a single core.

    Cheers,
    Andrew Ku
    TomsHardware.com
  • -2 Hide
    lradunovic77 , February 24, 2011 1:23 PM
    I say keep your desktop active all the time. I am running i980x overclocked to 4.0Ghz and there is no way i will put my computer into any type of power saving mode, it is useless and power saving is just mimick. We are talking about very small amount of money over a year. Having Turbo option makes sense from certain point of view but bottom line is that it is just wasted silicon and pretty much useless.
  • 0 Hide
    vvhocare5 , February 24, 2011 1:24 PM
    "The problem is that any price above $2/GB is going to be a hard sell unless you're an early adopter by nature. Our choices in recent System Builder Marathon stories reflect this. Look at our December $1000 PC."

    Overall a good article. Anyone into MTBF's will find that one page uninforming and anyone not into it is likely lost.

    I would disagree with that statement only in the sense that a $1000 PC is not going to be filled with high-end superior performing parts. So I dont see a reason to apologize for its price. The person who can afford a $3000+ PC isnt going to blink buying the 240G model and will likely see it as entirely reasonable.

    Me? I think I have found my next ex-drive.....

  • 0 Hide
    acku , February 24, 2011 1:35 PM
    Quote:
    so as i said, will OC increase the scores a bit?

    and what about power saving enabled?


    None of our tests were executed in an environment that allowed any idling. Furthermore, we disabled CPU throttling. Power saving was enabled in the sense that the display was allowed to turn off, which is part of the default profile in Windows.

    OCing may increase performance, but only to the extent that the bandwidth will support it. As I mentioned, PCMark throttles a single core up to 100%. It isn't a sustained trend.
  • 0 Hide
    bto , February 24, 2011 1:39 PM
    on your 1000 dollar gaming system, I'd rather have a vertex 3 than two 460's hell even an agility 2... and still afford better than a 460.
  • 0 Hide
    bto , February 24, 2011 1:42 PM
    But then that's me, and to quote the great Inigo Montoya, "I hate wait" and most games I play are not bleeding edge, I also work on my computer, play HD movies and copying time makes me angry when I'm moving files. Buy an ssd, and later spend 60 bux on a 1tb drive down the road.
  • 0 Hide
    Anonymous , February 24, 2011 1:45 PM
    There is a minor typo in the vertex 3/ vertex 3 pro comparison table - sequential read performance appears twice instead of sequential read and sequential write (the accompanying text sorts it out though in the end).
  • 0 Hide
    acku , February 24, 2011 1:49 PM
    Quote:
    There is a minor typo in the vertex 3/ vertex 3 pro comparison table - sequential read performance appears twice instead of sequential read and sequential write (the accompanying text sorts it out though in the end).


    Sorry about that. Fixed!
  • 1 Hide
    acku , February 24, 2011 1:56 PM
    Quote:
    on your 1000 dollar gaming system, I'd rather have a vertex 3 than two 460's hell even an agility 2... and still afford better than a 460.


    I completely understand that sentiment. Keep in mind that 460 prices dropped after our December System Builder Marathon. The fact remains that a decent CPU along with a SLI or CrossFire config will likely put the kibosh on any SSD choice. With a gaming rig, you are going to want a performance SSD, which means those lower end options almost go out the door. In any case, if you end up choosing a graphics card that runs at least $200, you'll hard to fit a SSD into the budget. It isn't impossible the way prices are falling, but you will likely be relying heavily on rebates or special deals.
  • 0 Hide
    acku , February 24, 2011 2:00 PM
    Quote:
    @ Andrew Ku

    thanks for the clarification. :) 


    No problem! We're here to answer any question.
  • 0 Hide
    bto , February 24, 2011 2:16 PM
    ackuI completely understand that sentiment. Keep in mind that 460 prices dropped after our December System Builder Marathon. The fact remains that a decent CPU along with a SLI or CrossFire config will likely put the kibosh on any SSD choice. With a gaming rig, you are going to want a performance SSD, which means those lower end options almost go out the door. In any case, if you end up choosing a graphics card that runs at least $200, you'll hard to fit a SSD into the budget. It isn't impossible the way prices are falling, but you will likely be relying heavily on rebates or special deals.


    Forgot to mention: Thank you for the article!
    I love SSD info I used to have 4 of the gigabyte I-RAM cards that were bootable in RAID 0 to get some similar results (two I-RAM were double stick taped to my case wall with pci flexible riser cards to make them all fit. I was hooked long before that obviously. Silence is also a golden feature that you do not realize until you have an already quiet system and remove the HDD.

    also to quote myself: "I hate Rebate" as probably everyone else does.
    Even the Vertex 2 60GB is down to $105 so for $35 more (which now you'd probably save more than $35 getting same components) You get a good ssd, later (if immediate budget did not permit) you can drop in a 1-3 TB hdd for storage. Since you already have 60GB it can wait a paycheck or two. replacing main drive later with SSD requires imaging which doesn't always work well, well at least it didn't used to. I had to try three different imaging programs before it came across properly (acronis, ghost, active disk image) I have an idea also for a fun article. Build an extremely small pc. Possibly with a 1.8" SSD to go in a car. with mii itx it would be doable and with ssd you'd not have to worry about the HDD crashing over speed bumps. Or do an article of a mini itx that lan party gamers could stick on the back of their monitor. I've replaced a case door on a silverstone with a 24" samsung before (wiring it in and all) like an Imac.
  • 1 Hide
    binoyski , February 24, 2011 2:52 PM
    If there was a time to save my money for a pc build, it was the time that Sandy Bridge launched. OMG! LGA 2011 will be the "GOLDEN AGE" for pc enthusiast!

    - A superfast SSD
    - Thunderbolt(Lightpeak)
    - 4-8 cores Ivy Bridge CPUs

    And I just hope that Bulldozer will come out w/ a BANG so prices will be lower!
  • -1 Hide
    notsogosu , February 24, 2011 3:00 PM
    Am i the only one this article and then rundown to anandtech to read their version? :S
  • 2 Hide
    restatement3dofted , February 24, 2011 3:07 PM
    notsogosuAm i the only one this article and then rundown to anandtech to read their version? :S


    Probably not, but so far, you're the only person that seems to be impressed enough with themselves to post about it...
  • 0 Hide
    LordConrad , February 24, 2011 3:59 PM
    I love how they boast about AES 256-bit protection. I'm no expert, but considering the recent attacks on AES 256, I think think AES 128 is more secure.

    http://eprint.iacr.org/2009/317
  • 0 Hide
    alidan , February 24, 2011 5:01 PM
    thanks for incorporating the SATA 3Gb/s configurations. i think there were some interesting numbers, at least when considering that while in 6Gb/s the drives preformed better, but when moved to 3Gb/s other 3Gb/s drives preformed better, still a bit tired from just waking up, ill go through it again later to see if i missed a reason for this happening.
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