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Steady State Performance (Worst Case) And TRIM

Intel SSD 520 Review: Taking Back The High-End With SandForce
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Clean Performance

Fresh Out Of Box PerformanceFresh Out Of Box Performance

In order to examine how an SSD might perform over time, we first fill up the user-accessible space with an incompressible sequential write, dirtying it up. The point is to replicate a worst-case situation where you find every available block written-to, leaving none free for the controller to use without first performing garbage collection.

Dirty Performance

Dirty Steady StateDirty Steady State

Since all user-accessible blocks contain data, garbage collection (which includes wear-leveling) needs to kick in. At this point, in order to write to the drive, existing blocks need to be shuffled around. Over-provisioning is the reserved space where this is allowed to happen.

According to Iometer, we should expect just under 400 MB/s right out of the box in sequential reads and writes. Indeed, sequential writes aren't penalized at all. SandForce's technology does most of its garbage collection in the foreground, so peak write speeds remain optimal.

Yet, strangely, after filling the drive, compressible read performance falls to ~200 MB/s. This is weirdness. That reads suffer and writes don't really doesn't make sense. Although we can't pin a cause on this behavior, we spent hours retesting and confirming our results.

Rerunning this test with a 60 GB Vertex 3 yields the same results, suggesting that this is something we'd see from any SandForce-based SSD.

Torture Performance

There's one other steady state to consider, and it involves overwriting the original dirty state with 4 KB random writes. Because the drive is already full of data, the controller can't write to available blocks. When we start writing with sequential data again, we force garbage collection to occur. This is a far more strenuous exercise than the preceding test as a consequence of data fragmentation.

Torture Steady State: Sequential Speeds After 1 Hour IdleTorture Steady State: Sequential Speeds After 1 Hour Idle

This exercise tends to emphasize background garbage collection, which, as we just noted, doesn't apply to SandForce. As a result, leaving the SSD idle won't help an SSD 520 as much as it might a Samsung 830, for instance.

Increasing data fragmentation on the drive causes compressible sequential reads to fall to 100 MB/s. This is what you'd see on any SandForce-based SSD though; it's not unique to Intel's.

TRIM Performance

Although idle time is less impactful on SandForce-based SSDs due to their foreground garbage collection, it is possible to recover compressible read performance by triggering the TRIM command. This occurs when you empty your Recycle Bin. Write speed still suffers because SandForce's controller delays block recovery until it actually needs to write.

Although idle time has less of an impact on SandForce-based SSDs due to their foreground garbage collection, it is possible to recover compressible read performance by triggering the TRIM command. This occurs when you empty your Recycle Bin. Write speed doesn't recover, however, because SandForce's controller delays the action until it actually needs blocks to write.

Fortunately, this may never be an issue for you. It only applies once you've written data to every block. And that's only likely to happen in an operating environment without TRIM support or if you RAID two SandForce-based SSDs together.

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  • -8 Hide
    Anonymous , February 6, 2012 3:04 PM
    Hmmm, maybe I missed a good excuse, but I'd like to see the Octane in these tests.
  • 2 Hide
    phamhlam , February 6, 2012 3:11 PM
    I love Intel SSD. 128GB for about $210 isn't bad. It is just hard to not chose something like a Corsair GT 120GB that cost $150 with rebate over this. I would always put a Intel SSD in a computer for novice since it is reliable.
  • 3 Hide
    thessdreview , February 6, 2012 3:32 PM
    Nice Review!
  • 0 Hide
    jaquith , February 6, 2012 3:59 PM
    Nice article :) 

    Just need more SSD's to compare, I'd like to see similar tests done with 120GB...180GB...256GB and several more brands. Further, as I mentioned before in the other article please list the exact model numbers and OEM specs including their 4KB IOPS; otherwise folks don't understand the results and if relying on this a purchasing will have in many cases a 4 in 5 chance of selecting the wrong SSD.

    Prior article - http://www.tomshardware.com/reviews/sata-6gbps-performance-sata-3gbps,3110.html
  • -3 Hide
    theuniquegamer , February 6, 2012 3:59 PM
    costly but i think reliability comes at a price. These ssds are best for enterprises . If the price will be little lower then the common user can afford these and get a good reliable ssd.
  • 1 Hide
    danraies , February 6, 2012 5:55 PM
    These prices are lower than I thought. $20-$40 extra (depending on the comparison) for peace-of-mind is not outrageous.
  • 2 Hide
    acku , February 6, 2012 6:02 PM
    carn1xHmmm, maybe I missed a good excuse, but I'd like to see the Octane in these tests.


    We didn't have the Octane on hand in the 256 GB capacity, but we'll be sure to make that side by side comparison down the road.

    phamhlamI love Intel SSD. 128GB for about $210 isn't bad. It is just hard to not chose something like a Corsair GT 120GB that cost $150 with rebate over this. I would always put a Intel SSD in a computer for novice since it is reliable.


    Excellent point. Price is always a fickle thing.

    thessdreviewNice Review!

    Thanks Les. :) 

    jaquithNice article Just need more SSD's to compare, I'd like to see similar tests done with 120GB...180GB...256GB and several more brands. Further, as I mentioned before in the other article please list the exact model numbers and OEM specs including their 4KB IOPS; otherwise folks don't understand the results and if relying on this a purchasing will have in many cases a 4 in 5 chance of selecting the wrong SSD. Prior article - http://www.tomshardware.com/review [...] ,3110.html


    We'll keep that mind for future reviews. However, we already list model and firmware on the test page.

    Cheers,
    Andrew Ku
    TomsHardware.com
  • 6 Hide
    willard , February 6, 2012 6:03 PM
    bildo123Getting out of standby on my HDD is a matter of seconds.

    And with an SSD, your computer comes out of standby faster than your monitors do. Not kidding.
  • 7 Hide
    mrkdilkington , February 6, 2012 6:08 PM
    Anyone else disappointed Intel isn't producing their own high end chipset? Been waiting to upgrade my X25-M for a while now (Intel 320 isn't a big upgrade) but might just go with Samsung.
  • 0 Hide
    boletus , February 6, 2012 6:49 PM
    Good to see Intel throw its hat into the ring for the prosumer market. We should be able to expect performance and out-of-the-box functionality (as opposed to theoretical endurance) for the amount of money these devices cost. As the article repeatedly infers, this has not always been the case to date (although the last year has seen some major kinks worked out). Competition at the mid to upper end of the market will lead to higher expectations.
  • 1 Hide
    universalremonster , February 7, 2012 12:26 AM
    Quote:
    Anyone else disappointed Intel isn't producing their own high end chipset? Been waiting to upgrade my X25-M for a while now (Intel 320 isn't a big upgrade) but might just go with Samsung.


    Yes, I'm with you on that one. I've had an Intel 320 128Gb SSD for quite some time now and have nothing but the greatest things to say about my particular experience with it. I purposely held off from buying the Marvell controller 510 in hopes that the next refresh would have a new Intel made 6Gb controller. One thing I am curious about, does the new 520 still have the Intel Toolbox software with it? I have gotten alot of use out of it with my current drive and would really hate to not have it on a new one.
  • 0 Hide
    acku , February 7, 2012 12:29 AM
    universalremonsterYes, I'm with you on that one. I've had an Intel 320 128Gb SSD for quite some time now and have nothing but the greatest things to say about my particular experience with it. I purposely held off from buying the Marvell controller 510 in hopes that the next refresh would have a new Intel made 6Gb controller. One thing I am curious about, does the new 520 still have the Intel Toolbox software with it? I have gotten alot of use out of it with my current drive and would really hate to not have it on a new one.


    You can use the Toolbox software with the SSD 520. It will however not work with other SF drives.

    Cheers,
    Andrew Ku
    TomsHardware.com
  • 0 Hide
    Anonymous , February 7, 2012 12:47 AM
    Andrew, could you please comment on the encryption capabilities of the new drive. Does it support AES encryption like the Intel 320? Is there an option for pre-boot? Thanks in advance!
  • 2 Hide
    compton , February 7, 2012 3:03 AM
    Andrew,

    Your SSD investigations/reviews/history lessons are Tier 1.


    But I always get curious when Intel starts on and on about how it has the best NAND around. It's not that I even doubt them when they say this, but AFAIK Intel/Micron/IMFT are made and binned in the same place.

    IMFT is supposed to be 49% Intel and 51% Micron-owned. Now both companies' own drives are stocked with what I presume is the best available NAND at that price point, but how did Intel get the reputation of having better NAND? (and if I'm honest, there is at least some evidence that it does). Micron doesn't run around talking up their NAND as much as they should, and this makes me think that the details of the IMFT arrangement are probably pretty strange. In a blind taste test, they taste pretty similar.

    But not all Micron NAND is created equal, nor is Intel's (for example, does Kingston really get Intel's top shelf shtuff?). The IMFT NAND used in so many drives today runs the gamut from fantastic down to mediocre, only one step above Hynix's too-dirty-for-television flash. I'm probably the one person on this planet that wants to know more about Intel, Micron, and their bastard love child, IMFT.
  • 0 Hide
    nikorr , February 7, 2012 4:15 AM
    So, does this SandForce's SF-2281 controller has the bug as well?

    Or it is already fixed?

    Or they have replaced it with a new version?
  • 0 Hide
    dragonsqrrl , February 7, 2012 6:11 AM
    nikorrSo, does this SandForce's SF-2281 controller has the bug as well?

    As far as Anand can tell... no.

    http://www.anandtech.com/show/5508/intel-ssd-520-review-cherryville-brings-reliability-to-sandforce


    Intel's SF2281 implementation seems to be stable, and BSOD free.

  • 1 Hide
    DjEaZy , February 7, 2012 8:38 AM
    ... my OCZ Vertex 3 is still strong...
  • 0 Hide
    triny , February 7, 2012 9:00 AM
    I have a crucial 128 my next will be Samsung
  • 2 Hide
    TEAMSWITCHER , February 7, 2012 11:44 AM
    Thank you for the OS X benchmarks! There are real differences between Windows 7 and OS X and having these benchmarks helps Mac users make better upgrade decisions.
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