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Results: Write Saturation And Over-Provisioning Tests

SanDisk X210 256 And 512 GB: Enthusiast Speed; OEM Reliability
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Random Performance Over Time

A saturation test consists of writing to a drive for a specific duration with a defined workload. Technically, this is an enterprise-class write saturation test, where the entire LBA space of the SSD is utilized by a random write at high queue depths.

This is 500 minutes worth of one-minute averages, with a 20 minute breakout on a per-second basis. Again, this sort of arbitrary workload on a fresh drive results in a peak of just 22,000 IOPS (though few random workloads will continuously pepper the entire LBA space with random writes at a queue depth of 32). In this test specifically, SanDisk's clever nCache technology imparts lower performance. In most of the workloads the X210 will be exposed to, nCache should do the opposite, speeding up benchmarks instead of the other way around.

As far as the raw data goes, our 20-minute slice of steady-state performance breaks down fairly well considering the X210 has just 7% spare area to rely on. It averages 4445 IOPS, showing a minimum of 2472 IOPS and a maximum of 7384. That's not bad. But we want to know more. Perhaps a quick look at various levels of over-provisioning will tell us something.

Over-Provisioning

We can't truly over-provision a drive in the lab. There are numerous ways to trade capacity for better performance; we could convince the OS that our drive has fewer logical block addresses for example, but the SSD knows otherwise. Even so, certain workloads are much better off if we sacrifice a bit of capacity. That leaves more room for the drive to perform background processes (like garbage collection), and the results can be profound, even if the controller still has to map the existing space. If we start with the number of bytes available to the user (256,052,966,400 in this case), we can run the write saturation test again. Each successive time (after a secure erase), the amount of accessible space is reduced.

The following chart shows five separate points: the full span (as above), 93%, 84%, 50%, and 25%.

There is a near-doubling of performance when we sacrifice an additional 7% of the addressable LBA space. The next step up, leaving 84% of the drive's capacity, allows the X210 to sustain almost 17,000 IOPS. To multiply that number, you need to give up 50% of the 256 GB SSD's space, a hefty price to pay, for sure.

Lastly, this is a 20 minute breakdown of the same over-provisioning experiment taken from the end of the multi-hour plot and displayed in one-second increments. As you can see, the spread between minimum, maximum, and average IOPS can get pretty massive.

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  • 1 Hide
    vertexx , January 15, 2014 3:15 AM
    I logged onto Tom's this morning totally expecting a Kaveri review. What's up?
  • 2 Hide
    TeraMedia , January 15, 2014 9:00 AM
    Is the warranty 5 years or 3? Last page says one thing, an early page says another.Decent review, decent drives. Has THG considered doing something similar to what the car mags do, where they take certain products and use them for a year? It would be great to capture that kind of longer-term info on certain types of products, especially the kind that wear out (ODDs, fans, cases, HDDs, SSDs, etc.).
  • 1 Hide
    Quarkzquarkz , January 15, 2014 9:05 AM
    What about Samsung SSD pro 512GB? I bought 2 of these and on that chart is only 128 and 256GB
  • -1 Hide
    vmem , January 15, 2014 9:07 AM
    @vertexxthere isn't anything particularly exciting about Kaveri going by Anand's review. I shall want for the A10 version with higher clocks
  • 2 Hide
    smeezekitty , January 15, 2014 11:05 AM
    MLC with 5k write endurance!And affordable and fast?We may very well have a new solid contender in the SSD world
  • 1 Hide
    eklipz330 , January 15, 2014 3:47 PM
    anandtech has one? sweeeet, later tom's!
  • 3 Hide
    RedJaron , January 15, 2014 3:52 PM
    I agree with Chris. I don't need the fastest bench speeds in a SSD. Most models now are very fast and the user won't see the performance difference. I want reliability and longevity. Looks like this is a smart choice for any new builder.
  • 2 Hide
    Phillip Wager , January 15, 2014 9:54 PM
    sweet finally another company that can compete with intel's 5 year warrenty!
  • 2 Hide
    jake_westmorley , January 16, 2014 2:31 AM
    Can we PLEASE have some normal graphs for once? The graph on page 5 in stupid 3D is so bad it's comical. The "perspective" effect completely screws with the data. This has zero added value and is almost as bad as still using clipart.
  • -1 Hide
    Duff165 , January 16, 2014 2:35 AM
    I find it hard to believe that the author has had "literally dozens of SSd's die" on him over the years. This would suggest that many systems have contributed to the demise of many of the SSD's being used, which seems somewhat outlandish. Just the cost factor involved in the purchase of so many SSD's and then having over a dozen of them fail, supposedly also from various companies, since if they were all from the same company it would not really be conducive to good sales. One, or maybe two I could live with, but dozens? No.
  • 1 Hide
    jabliese , January 16, 2014 9:18 AM
    @Duff165 I would respond to your ignorance, but I really, really dislike this "new" comment system that Tom's has foisted on us.
  • 0 Hide
    smeezekitty , January 16, 2014 11:02 AM
    Quote:
    @Duff165 I would respond to your ignorance, but I really, really dislike this "new" comment system that Tom's has foisted on us.


    Agreed. Now it is truly screwed more than ever.
    WTH is will the continuously scrolled unrelated articles, dropped newlines and just plain broken comments.
  • 2 Hide
    RedJaron , January 16, 2014 11:23 AM
    Quote:
    I find it hard to believe that the author has had "literally dozens of SSd's die" on him over the years. ... One, or maybe two I could live with, but dozens? No.

    For the typical user that only has a few systems at the same time, yes. For someone who works with dozens of systems, the chance for one of them to fail goes up. Constantly building, testing, and reconfiguring machines means you're constantly imaging and re-imaging drives, which wears them out much faster than normal. Perhaps it was a little exaggerated, but it's definitely possible
  • 0 Hide
    tripleX , January 16, 2014 7:05 PM
    Lol. All of the work that went into making page 5 seem like some super-complicated test. That is just HDTune, which can be ran with the click of a button and hardly requires and entire page and horrible graph for explanation.
  • 1 Hide
    stewieco , January 17, 2014 9:08 AM
    Question: Can this drive be used on a personal laptop??
  • 2 Hide
    smeezekitty , January 18, 2014 2:53 PM
    Quote:
    Question: Can this drive be used on a personal laptop??


    I don't see why not
  • 0 Hide
    LFDRTechPro , January 20, 2014 5:14 PM
    There's actually a pretty huge difference between MLC-SLC translator based emulation and the way that tlc can behave electronically(physically) as SLC independently at the bottom of the translation layer. MLC-emulation has a partially positive and partially negative effect on translator stability, but with a robust controller(Marvell), the net effect on reliability is positive.With TLC as SLC, the effect is nearly perfectly proportionate to having SLC physically present.In fact, it is possible(with manufacturer tools) to take just about any TLC device like a 64GB usb flash drive and make it electronically indistinguishable(nearly) to a ~22Gb TLC flash drive in respect to performance, endurance, etc...MLC emulation is much more nuanced.
  • -1 Hide
    mwearl , January 20, 2014 6:52 PM
    @Duff165. It's very believable that the author could have had dozens of SSD failures, especially if he used some brands like Mushkin. We were building systems using their 120GB SSDs and had nearly 75% failure rate within the first 6 months. Since then, we have used primarily Kingston with a few Intel and Crucial SSDs and haven't had a single failure since.
  • -1 Hide
    mwearl , January 20, 2014 6:54 PM
    @Duff165. It's very believable that the author could have had dozens of SSD failures, especially if he used some brands like Mushkin. We were building systems using their 120GB SSDs and had nearly 75% failure rate within the first 6 months. Since then, we have used primarily Kingston with a few Intel and Crucial SSDs and haven't had a single failure since.
  • 2 Hide
    gwolfman , January 21, 2014 10:31 AM
    Since the major difference between the X210 and the Extreme II is the firmware, can you please test the Extreme II on the new DriveMaster TRIM test and see if they behave the same? SanDisk just turned into a new favorable option for me for my next drive.
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