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Results: Latency And Performance Consistency

Samsung 850 Pro SSD Review: 3D Vertical NAND Hits Desktop Storage
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Normally, I'd just use a garden variety workload generator for testing latency and performance consistency. It's simple enough that you could train a medium-smart kitten to do this stuff. But I like ULINK's platform; it gives me a common foundation for running benchmarks. That's not a big deal for some metrics, but it's more important for others. I have to use several different machines for testing with DriveMaster, due mostly to the length of time these workloads eat up. Two comparable systems deliver identical performance with DM2012.

Latency

ULINK's Latency test does things in a slightly different way than I've presented in the past. First, the drive is secure erased. Next, it is filled twice sequentially, then once with random writes. Immediately after, the latency test begins.

This script tests sequential one-sector accesses, sequentially testing 512 bytes. Do that 2 million times for reads and two million times more for writes, and presto. You get one result for reads and another for writes in the blink of an eye.

Samsung's hardware looks impressive. Not only do the 850 Pros serve up low latencies, but the 840 EVO and 840 Pro also hold their own. It takes the other contenders much longer to complete reads and writes under the same conditions, ending with Crucial's MX100. We'll do more of this testing on the drives waiting for reviews, but you can already see that going the budget route has negative implications.

Performance Consistency

This is another test I'd typically run differently. I don't even really like the phrase performance consistency. But I do like ULINK's PerfCon test. It offers six test cases: 4 KB read, 4 KB write, and 50% read/50% write in both aligned and unaligned boundaries. I won't bore you with the outcomes of all six test cases. Instead, I'll stick to the 50% read/50% write 4 KB aligned measurement.

The trick here is that after the same preconditioning used above, 1000 data points are generated one second apart. The 95.5th-percentile slowest result is divided by the average IOPS to yield one performance number reflecting consistency as a percentage. Absolute transactional performance is factored out of that number, so I display average, minimum, and maximum IOPS in a separate chart.

As you can see, the average, maximum, and minimum IOPS results are more even towards the top. In this 4 KB random workload split between reads and writes, steady state 4 KB write performance gets bolstered by reads. But it's more difficult for some drives to maintain when the workload is mixed.

Sure enough, Intel's SSD 730 ends on top, owing to its high average I/O performance. The Samsungs filter in behind. There's almost 2.5x as much difference between the slowest  and fastest averages. But how do the percentages play out?

The Vector exhibits some strange results, but 65% isn't bad for the MX100. Intel's SSD 730 attains an impressive 87%, and the 850 Pro contingent (led by the 256 GB capacity point) score a win. Each is above 91%, which is just great. Even without additional over-provisioning, the 850 Pros dominate in our look at consistency.

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  • 0 Hide
    iknowhowtofixit , June 30, 2014 8:19 PM
    Hmm, what's next for SATA? SATA4? SATA 3.2 (SATA Express) doesn't look like a long term solution. PCI-E is fine, but SATA is still so convenient.
  • 2 Hide
    MoulaZX , June 30, 2014 8:34 PM
    I 'just' ordered 2x Samsung EVO 120GB a few hours ago, then I stumbled onto this article. Damn it! Damn it! Damn it! Every freaking time I run into this, be it Storage, CPU, or GPU.... -_-
  • 2 Hide
    cryan , June 30, 2014 8:41 PM
    Quote:
    I 'just' ordered 2x Samsung EVO 120GB a few hours ago, then I stumbled onto this article. Damn it! Damn it! Damn it! Every freaking time I run into this, be it Storage, CPU, or GPU.... -_-


    I don't know if this really changes anything for you. Two EVOs are still going to be better than one 850 Pro in [most] every way. But I understand the sentiment!

    Christopher Ryan
  • 5 Hide
    lp231 , June 30, 2014 9:05 PM
    Quote:
    I 'just' ordered 2x Samsung EVO 120GB a few hours ago, then I stumbled onto this article. Damn it! Damn it! Damn it! Every freaking time I run into this, be it Storage, CPU, or GPU.... -_-

    You just ordered a few hours ago. Just cancel your order if you really want this 850 Pro.
  • 6 Hide
    tomfreak , June 30, 2014 9:12 PM
    10yrs warranty, may be finally I have a reason to buy SSD. lol
  • 7 Hide
    g-unit1111 , June 30, 2014 9:42 PM
    Quote:
    10yrs warranty, may be finally I have a reason to buy SSD. lol


    I can guarantee that in 10 years you won't own that drive anymore. :lol: 
  • 3 Hide
    10tacle , June 30, 2014 9:52 PM
    I still have several 8-10 year old drives laying around between 80GB-150GB. I mostly use them as external drives for backing up USB thumb drives and other files that aren't large volume.
  • 1 Hide
    helper800 , June 30, 2014 9:54 PM
    Hoping for some SATA 12gbs (or more) transfer speeds in the coming years.
  • 0 Hide
    razor512 , June 30, 2014 9:56 PM
    Will overclocking the bus that the sata controller is on impact the performance?

    Can you test on an AMD platform which makes it easier to over clock that bus and some of the connected components?
  • -1 Hide
    BestJinjo , July 1, 2014 2:05 AM
    Looking forward to future generations of 3D Vertical Nand on M.2 / M.2 Ultra interface. Too bad SATA 3 is all maxed out and the next generation standards are not yet mainstream for the masses which is holding back SSD performance. As far as this drive goes, it's only slightly faster than MX100 but costs double. I don't think it's worth it. MX100 512GB sounds like a perfect stop-gap until M.2/SATAe drives arrive with 1-1.5TB/sec throughput. Perhaps Samsung will give us 95% of the performance for a fraction of the price in the 850 EVO.
  • 0 Hide
    MoulaZX , July 1, 2014 4:49 AM
    Quote:
    Quote:
    I 'just' ordered 2x Samsung EVO 120GB a few hours ago, then I stumbled onto this article. Damn it! Damn it! Damn it! Every freaking time I run into this, be it Storage, CPU, or GPU.... -_-


    I don't know if this really changes anything for you. Two EVOs are still going to be better than one 850 Pro in [most] every way. But I understand the sentiment!

    Christopher Ryan


    Not quite. One is for my Desktop, the other is for my Father's Desktop.

    For my Desktop, I'll be stepping up from 2x OCZ Vertex 2 60GB in RAID 0. Hope it'll be worth it...
  • 0 Hide
    MoulaZX , July 1, 2014 5:00 AM
    Quote:
    Quote:
    I 'just' ordered 2x Samsung EVO 120GB a few hours ago, then I stumbled onto this article. Damn it! Damn it! Damn it! Every freaking time I run into this, be it Storage, CPU, or GPU.... -_-


    I don't know if this really changes anything for you. Two EVOs are still going to be better than one 850 Pro in [most] every way. But I understand the sentiment!

    Christopher Ryan


    Not quite. One is for my Desktop, the other is for my Father's Desktop.

    For my Desktop, I'll be stepping up from 2x OCZ Vertex 2 60GB in RAID 0. Hope it'll be worth it...
  • 1 Hide
    cpy , July 1, 2014 5:19 AM
    Why does tom hardware looks like website from 1990? This page is narrow as hell!
  • 2 Hide
    Flying-Q , July 1, 2014 5:40 AM
    Quote:
    Why does tom hardware looks like website from 1990? This page is narrow as hell!

    That would be to give more room for the sidebar adverts.
  • 0 Hide
    Novuake , July 1, 2014 6:02 AM
    Impressive, didn't think some of these numbers were possible via SATA3.

    But the limit has now been reached in almost every way.

    Which solution will stick? Anyone care to guess?
  • 0 Hide
    crawlgsx , July 1, 2014 6:14 AM
    Eh, unimpressed. Sure its a nice bump but when I look at how long the 840 Pro has been on the market and compare it to the increase to the soon coming 850 Pro, to say the least it doesn't make me want to run out and replace my 840's.
  • 3 Hide
    cryan , July 1, 2014 7:44 AM
    Quote:
    Hmm, what's next for SATA? SATA4? SATA 3.2 (SATA Express) doesn't look like a long term solution. PCI-E is fine, but SATA is still so convenient.


    I disagree. SATA Express melds the convenience of SATA and pcie performance. With NVMe and Gen 3 PCIe, I think there WILL be much to like.

    Christopher Ryan
  • 0 Hide
    RedJaron , July 1, 2014 8:21 AM
    That much speed for that little power draw? Impressive.
  • -1 Hide
    arneberg , July 1, 2014 8:21 AM
    SATA Express haw to wide Cables as bad as the old IDE Cables M.2 or PCIE cards
  • 1 Hide
    xenol , July 1, 2014 8:23 AM
    Part of me doesn't care about bandwidth. I've had Windows 7 load up much faster (as in the throbber didn't get to finish) on a laptop with a SATA 3Gbps interface than a desktop using the 6Gbps interface. And most of the time file accesses are small, but many.

    I'd rather start seeing IOPS crank up to RAM levels.
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