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Results: 128 KB Sequential Writes

Samsung 840 EVO SSD: Tested At 120, 250, 500, And 1000 GB
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128 KB Sequential Write

This is where the analysis gets more complicated. When we tested SanDisk's Extreme II, our Iometer-based setup yielded specific, detrimental results. They weren't terrible, but we did notice that a larger-than-typical LBA range upset the drives. We suspect their behavior was attributable to SanDisk's nCache technology.

In the same way, the length of the testing at each queue depth means our results are stacked against the 840 EVO's maximum speed, penalizing the larger models due to their comparatively larger Turbo Write caches.

Take the 120 GB 840 EVO as an example. It should be hitting ~400 MB/s. But as I explained, it sets aside 9 GB of capacity to cache 3 GB of writes. Overflow is written to the remaining three-bit-per-cell memory at a slower rate. Samsung's 250 GB 840 EVO starts almost 100 MB/s faster. If we stopped this test after just a couple of seconds, though, you'd see throughput closer to 500 MB/s since the cache wouldn't be full yet.

The 500 GB and 1 TB versions can't quite hit the 500+ MB/s we'd expect because, again, we're exceeding the capacity of their respective caches. But more space set aside and additional parallelism facilitate results that come closer to Samsung's maximum specified Turbo numbers.

Somewhat unsurprisingly, the 120 GB 840 EVO butts up against the 250 GB 840. Samsung's older drive doesn't enjoy the faster controller frequency or on-drive caching. Those features help the 120 GB 840 EVO almost keep up with a vanilla 840 almost twice its size.

The 250 GB 840 EVO matches Intel's SSD 335 working on non-compressible data, and the two larger 840 EVOs nearly claim top positions through our test.

Samsung's Turbo Write technology propels the 120 GB 840 EVO into a spot between the 250 and 120 GB 840s. The 250 GB 840 EVO is sandwiched between a pair of Intel drives.

The 840 EVOs don't achieve their maximum numbers in our Iometer test, but 460 MB/s certainly isn't an outcome we'd dismiss. 

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  • 1 Hide
    Someone Somewhere , July 25, 2013 5:37 AM
    Surely it would make sense to compare it to the vanilla SSD840. Also, there's no 840 Pro in the power charts.

    While the 1TB drive coming down to ~65c/GB is nice, seeing the 120 GB drives get near there would be nice. Especially since this is meant to be the value king.
  • -2 Hide
    drwho1 , July 25, 2013 6:45 AM
    I have 2 840 pro 512 GB SSD's (1 on my notebook 1 on my PC)

    I got them on a sale on Newegg for around $500 for both of them. :) 

    A 1TB would be cool if I find it on sale....
    or maybe I should try out writing a letter to someone fat in some weird red costume...
  • 5 Hide
    slomo4sho , July 25, 2013 7:45 AM
    The performance gap between the 840 Evo and 840 Pro is discouraging for the lower capacity models. I understand that the Pro is the flagship product but I was expecting less of a gap in in the 120GB models since this is a newer generation product and the 840 Pro is still based on the 21nm MLC NAND. However, the 1TB model is is a great choice for mass SSD storage. Lets hope the prices drop below $0.50 per GB soon.
  • 1 Hide
    Someone Somewhere , July 25, 2013 7:48 AM
    MLC is faster than TLC, and bigger node NAND is usually faster. Only reason to go smaller is price and power.
  • 0 Hide
    SteelCity1981 , July 25, 2013 8:20 AM
    I wonder if samsung plans on releasing a pro evo series since the regular series evo is to replace the older non pro versions.
  • -2 Hide
    razor512 , July 25, 2013 8:40 AM
    ripoff, high prices for triple level flash especially at 19mm, the lifespan will likely suck and their shortened warranty represents that.
  • 0 Hide
    master9716 , July 25, 2013 8:41 AM
    Cost for performance = Very High . ofcourse its not going to perform like a Pro but for the cost im amazed its that much better than the Regular 840.
  • 2 Hide
    expl0itfinder , July 25, 2013 10:00 AM
    Samsung makes some good looking drives. I'm loving the matte grey.
  • 0 Hide
    J_E_D_70 , July 25, 2013 10:09 AM
    Glad this review also refutes the perception of low TLC write endurance in normal desktop workloads. Been using a 128GB 840 in a daily-use desktop for eight months now and the endurance counter hasn't decremented at all. I'll have replaced the entire rig long before it wears out.
  • 4 Hide
    JohnnyLucky , July 25, 2013 10:38 AM
    Interesting review. I think the point to remember is that the 840 EVO is not a high end enthusiast ssd like the 840 Pro. Instead, consider the 840 EVO as a mainstream ssd suitable for most consumer and home office scenarios.
  • -2 Hide
    JohnnyLucky , July 25, 2013 10:38 AM
    Interesting review. I think the point to remember is that the 840 EVO is not a high end enthusiast ssd like the 840 Pro. Instead, consider the 840 EVO as a mainstream ssd suitable for most consumer and home office scenarios.
  • 1 Hide
    joshua305 , July 25, 2013 10:51 AM
    Very interesting article. I would love to see it compared to m-500 in the charts as that seems to be the really direct competition. Is the caching feature in magician windows only? No OSX or Linux?
  • 0 Hide
    joshua305 , July 25, 2013 10:52 AM
    Very interesting article. I would love to see it compared to m-500 in the charts as that seems to be the really direct competition. Is the caching feature in magician windows only? No OSX or Linux?
  • 0 Hide
    ssdpro , July 25, 2013 11:01 AM
    The question is, does it suffer from the sudden bricking some SSD (including the 840 Pro) experience? And is RAPID the first fruit from the Nvelo acquisition? If so that is a data-loss bonanza. I hope Tom's can check into that further as promised.
  • 0 Hide
    Azn Cracker , July 25, 2013 11:04 AM
    hmm was going to buy a regular 840 because it was on sale for $90. Think ill just hold off for the EVO
  • 0 Hide
    marraco , July 25, 2013 12:09 PM
    Nice, but I still run an X58 system, with slower SATA, so I can't take advantage of this.

    Samsung: I need this drive with 2 SATA connectors so it makes possible to create a virtual RAID, and squeeze the drive performance.

    Is clear that newer drivers are bottlenecked by the fastest SATA, so out of PCIE drives, virtual RAIDS are necessary.
  • 1 Hide
    MC_K7 , July 25, 2013 12:31 PM
    I really like that the new Evo 120GB is able to achieve 410 MB/s of write speed! That's such a big jump from the disappointing 130 MB/s of the previous 840 it replaces. When you think about it that was pretty much the same write speed as a mechanical drive lol.
  • 0 Hide
    MC_K7 , July 25, 2013 12:32 PM
    I really like that the new Evo 120GB is able to achieve 410 MB/s of write speed! That's such a big jump from the disappointing 130 MB/s of the previous 840 it replaces. When you think about it that was pretty much the same write speed as a mechanical drive lol.
  • 2 Hide
    MC_K7 , July 25, 2013 12:34 PM
    Sorry for the double-post guys the website is acting funny. I got "an error occurred" after trying to post the first comment, but it looks like it went through anyways.
  • 2 Hide
    cryan , July 25, 2013 12:52 PM
    You don't get the 120 GB's 410 MB/s all the time, but you should get a substantial increase in day to day activity. If you look at the Robocopy results, you'll see that if you try copying 16.2 GB worth of stuff it's not much faster. On the other hand, if you're just copying a few GB from one drive to another, the EVO 120 GB can be almost as fast -- almost -- as the 840 Pro.

    Regards,
    C. Ryan

    Quote:
    I really like that the new Evo 120GB is able to achieve 410 MB/s of write speed! That's such a big jump from the disappointing 130 MB/s of the previous 840 it replaces. When you think about it that was pretty much the same write speed as a mechanical drive lol.


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