Performance Consistency

Performance consistency tells us a lot about the architecture of these SSDs and how they handle internal defragmentation. The reason we don’t have consistent IO latency with SSD is because inevitably all controllers have to do some amount of defragmentation or garbage collection in order to continue operating at high speeds. When and how an SSD decides to run its defrag or cleanup routines directly impacts the user experience as inconsistent performance results in application slowdowns.

To test IO consistency, we fill a secure erased SSD with sequential data to ensure that all user accessible LBAs have data associated with them. Next we kick off a 4KB random write workload across all LBAs at a queue depth of 32 using incompressible data. The test is run for just over half an hour and we record instantaneous IOPS every second.

We are also testing drives with added over-provisioning by limiting the LBA range. This gives us a look into the drive’s behavior with varying levels of empty space, which is frankly a more realistic approach for client workloads.

Each of the three graphs has its own purpose. The first one is of the whole duration of the test in log scale. The second and third one zoom into the beginning of steady-state operation (t=1400s) but on different scales: the second one uses log scale for easy comparison whereas the third one uses linear scale for better visualization of differences between drives. Click the buttons below each graph to switch the source data.

For more detailed description of the test and why performance consistency matters, read our original Intel SSD DC S3700 article.

  SanDisk Extreme Pro SanDisk Extreme II Intel SSD 730 Intel SSD 530 OCZ Vector 150
25% Spare Area

Similar to the Extreme II, the IO consistency is just awesome. SanDisk's firmware design is unique in the sense that instead of pushing high IOPS at the beginning, the performance drops close to 10K IOPS at first and then rises to over 50K and stays there for a period of time. The higher the capacity, the longer the high IOPS period: the 960GB Extreme Pro takes ~800 seconds before the IOPS drops to 10K (i.e. the drive reaches steady-state). I do not know why SanDisk's behavior is so different (maybe it has something to do with nCache?) but it definitely works well. Furthermore, SanDisk seems to be the only manufacturer that has really nailed IO consistency with a Marvell controller because Crucial/Micron and Plextor have had some difficulties and their performance is not even close to SanDisk.

However, I would not say that the Extreme Pro is unique. Both Intel SSD 730 and OCZ Vector 150 provide the same or even better performance at steady-state, and with added over-provisioning the difference is even more significant. That is not to say that the Extreme Pro is inconsistent, not at all, but for a pure 4KB random write workload there are drives that offer (slightly) better performance.

  SanDisk Extreme Pro SanDisk Extreme II Intel SSD 730 Intel SSD 530 OCZ Vector 150
25% Spare Area


  SanDisk Extreme Pro SanDisk Extreme II Intel SSD 730 Intel SSD 530 OCZ Vector 150
25% Spare Area


TRIM Validation

To test TRIM, I filled the drive with sequential data and proceeded with 60 minutes of 4KB random writes at queue depth of 32. I measured performance with HD Tach after issuing a single TRIM pass to the drive.

TRIM works for sure as the write speed is at steady 400MB/s.


Introduction, The Drives & The Test AnandTech Storage Bench 2013
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  • LtGoonRush - Monday, June 16, 2014 - link

    The only improvements are idle power consumption and support for Low-Power DDR3, and this isn't really a mobile-targeted drive.
  • Oyster - Monday, June 16, 2014 - link

    10 years warranty. Love it. L.O.V.E. I.T. Thank you, SanDisk, for setting this trend. I'll surely wait, but I think this is exactly what I need for my next build.
    10 years... OMFG! Drool!
  • tential - Monday, June 16, 2014 - link

    It's a great warranty but I think ssds potential failure points are less than an hdd. (my speculation).

    When I saw that though it definitely peaked my interest. Would have purchased this drive if it had been an option as that warranty would definitely make me feel better as I hold onto my hardware for a long time.
  • MrSpadge - Tuesday, June 17, 2014 - link

    I'd still choose the MX100 over this any day. It's not like these drives are falling apart everywhere. And if you save the price difference between these drives you could use it to buy something significantly better in a few years, should the MX100 have failed by then (I wouldn't expect it to).
  • nathanddrews - Tuesday, June 17, 2014 - link

    This is pretty awesome:
  • havefunbob - Tuesday, June 17, 2014 - link

    that is really good test
  • binarycrusader - Monday, June 16, 2014 - link

    How exactly is this a no compromise drive when it doesn't offer encryption and it doesn't offer capaciyor-based power loss protection? Data integrity and security seem like pretty big compromises. Or is the SLC buffer seen as a sufficient substitute for a capacitor-based solution?
  • BillyONeal - Monday, June 16, 2014 - link

    It is a no compromise drive for the market it targets -- the consumer market. Few / no consumer-targeted drives have capacitors; pretty much all such drives are targeting the server market, such as Intel's SSD DC3700. Very few consumer drives offer TCG Opal, but some do, e.g. Samsung's 840 EVO.
  • binarycrusader - Monday, June 16, 2014 - link

    The author specifically mentioned disappointment at the lack of encryption, and the author, unlike you specifically used the phrase "only no compromise high-end SSD in the market" while simultaneously declaring Intel's 730 SSD, OCZ's Vector 150, and Samsung 840 Pro as being in that same "high-end" market. So it seemed rightfully bizarre to simultaneously proclaim it as a "no compromises" drive given the other drives the author also compared it to that are supposedly in the same market.

    Also, while you're right that few consumer-targeted drives have capacitors, the Crucial M500 does. And honestly, capacitors don't cost that much, but it's no wonder Intel's happy to let all of the other manufacturers fight over "razor-thin" margins.
  • Kristian Vättö - Tuesday, June 17, 2014 - link

    Because the Extreme Pro is the only high-end SSD without the compromises that the three other SSDs have. Intel SSD 730 and OCZ Vector 150 don't support any form of low-power states and are thus not suitable for laptops. The 840 Pro, on the other hand, lacks IO consistency. All three drives are in the same high-end performance market, thus I'm comparing the Extreme Pro with them.

    Crucial's drives have capacitors that provide power loss protection but they are the only drives along with Intel's SSD 730. However, you can get away without capacitors if the firmware is designed not to rely too much on the DRAM cache. I would certainly like to see OEMs use capacitors more in consumer-grade drives but on the other hand, I'm not sure if I consider it to be that big of a deal. We don't have a proper way to test power losses, so I don't want to give too much value to a feature that may or may not be needed.

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