Sequential Read/Write Speed

To measure sequential performance I ran a 1 minute long 128KB sequential test over the entire span of the drive at a queue depth of 1. The results reported are in average MB/s over the entire test length.

Desktop Iometer - 128KB Sequential Read (4K Aligned)

Low queue depth sequential read performance is among the better drives, but still slightly behind Samsung.

Desktop Iometer - 128KB Sequential Write (4K Aligned)

Write performance continues to be the Vector's strong suit, here only Intel's SSD 520 with easily compressed data pulls ahead.

AS-SSD Incompressible Sequential Performance

The AS-SSD sequential benchmark uses incompressible data for all of its transfers. The result is a pretty big reduction in sequential write speed on SandForce based controllers.

Incompressible Sequential Read Performance - AS-SSD

High queue depth sequential IO shows significant clustering at the top of the charts thanks to the limits of 6Gbps SATA. The Vector pushes performance pretty much as fast as possible here.

Incompressible Sequential Write Performance - AS-SSD

Switching to writes does shake loose some of the weaker competitors, but the Vector and 840 Pro still emerge as the strongest. Corsair's Neutron GTX does very well here.

Random IO Performance Performance vs. Transfer Size
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  • extide - Wednesday, November 28, 2012 - link

    Copy Performance is tied to the block size you use when reading and writing. IE if you read 4k at a time, then write 4k at a time, you will get different performance than reading 4MB at a time and then writing 4MB. So it largely depends on the specific app you are using. Copy isnt anything special, just reads and writes.
  • mark53916 - Thursday, November 29, 2012 - link

    Maybe I should have explained more:
    I have found that most USB keys and many SATA SSDs perform
    MUCH worse (factor of 10 and even up to more than
    300 decrease in performance) when reads and writes are mixed,
    rather than being a bunch of reads followed by a bunch writes.

    The reads and writes can be to random locations and there still
    can be a big performance it.

    A feel that a simple operating system copy of a large sequential
    file and a tree of a bunch of smaller files should be done since
    the two tests have shown me large performance differences
    between two devices that have the about the same:
    . sequential read rate
    . sequential write rate
    . Read/second
    . Writes/second
    when the reads and writes aren't mixed.

    I also found that HD Tune Pro File Benchmark sometimes shows
    significant (factor of 10 or more) differences between the
    Sequential 4 KB random single and 4 KB random multi tests.

    (For my own personal use, the best benchmark seems to be
    copying a tree of my own data that has about 6GB in about
    25000 files and copying from one 8GB TrueCrypt virtual disk
    to another on the same device. I see differences of about
    15 to one between stuff that I have tested in the last year
    that all show speeds limited by my 7 year old motherboards
    in sequential tests and all performing much slower with the
    tree copy tests.

    Since the tree is my ad-hoc data and my hardware is so old
    I don't expect anyone to be able to duplicate the tests, but I
    have given results in USENET groups that shows that there
    are large performance differences that are not obviously
    related to bottlenecks or slowness of my hardware.

    There could be something complicated happening that
    is due, for instance, in a problem with intermixing
    read and write operations on USB 3 or SATA interface
    that is dependent on the device under test but not
    due to an inherent problem with the device under test,
    but I think that the low performance for interleaved reads
    and writes is at least 90% due to the device under test
    and less than 10% due to problems with mixing
    operations on my hardware since some devices don't
    have a hit in performance when read and write operations
    are mixed and have sequential uni-directional performance
    much higher than 200MB/s on SATA and up to 134MB/s
    on USB 3.

    There could be some timing issues caused by having
    a small number of buffers (much less than 1000), only
    2 CPUs, having to wait for encryption, etc., but I don't
    think these add up to a factor of 4, and, as I have said,
    I see performance hits of much more than 15:1
    for the same device, and all I did was switch from copying
    from another flash device to the flash device under test
    to copying from one location on the flash device under test
    to another location. on the same device. Similarly, the
    HD Tune Pro File Benchmark Sequential 4 KB random single
    compared to 4 KB random multi with multi 4 or more
    takes a hit of up to 100 for some USB 3 flash memory keys,
    whereas other flash memory keys may run about the same speed
    for random single and multi as well as about the same speed for
    as the poorly performing device does for 4 KB random single.
  • MarchTheMonth - Wednesday, November 28, 2012 - link

    Anand, I just want to know what you think of as a difference with the new CEO sending a formal, official compared to the hand-written notes by Ryan. To me (an outsider), official letters bore me, as they are just a carbon copy of the same letter sent to many others.
    A handwritten note would mean more to me. Now, given that the handwritten note was more of a nudge, I can understand that perhaps a less "nudging" note would be more appreciated, but I digress.
    Just curious.
    -March
  • BrightCandle - Wednesday, November 28, 2012 - link

    Do you have more confidence this time that OCZ is actually being honest about the contents of their controller chip? Clearly last time you were concerned about OCZ's behaviour when you reviewed the Octane (both in terms of reviewing their drives and allowing them to advertise) and they out right lied to you about the contents of the chip, they lied to everyone until they got caught.

    This time do you think the leopard has changed its spots or is this just business as usual for a company that cheats so frequently?
  • gammaray - Wednesday, November 28, 2012 - link

    The real question is,

    Why pay for an OCZ Vector when you can get a Samsung 840 Pro for the same price??
  • jwilliams4200 - Thursday, November 29, 2012 - link

    Very good question.
  • Hood6558 - Wednesday, November 28, 2012 - link

    If these are priced to compete with Samsung's 840 Pro, only a die-hard OCZ fanboy would buy one, since the 840 Pro beats it in almost every benchmark, and is considered the most reliable brand, while OCZ has a long, rich history of failed drives, controllers, and firmware. Even if they were priced $50 below the Samsung I wouldn't buy one, at least not until they had 6 months under their belt without major issues. It get's old re-inventing your system every time your SSD has issues.
  • SanX - Thursday, November 29, 2012 - link

    Remember that excluding typed vs handwritten letter to Anand this is still 100% Ryan Petersen in each SSD
  • skroh - Thursday, November 29, 2012 - link

    I noticed that in the consistency testing, the Intel 330 seemed to outperform just about everything except the Intel 3700. That seems like a story worth exploring! Is the 330 a sleeper user-experience bargain?
  • jwilliams4200 - Thursday, November 29, 2012 - link

    For one thing, it did not look to me like the 330 had yet reached steady-state in the graphs provided. Maybe it had, but at the point where the graph cut-off things were still looking interesting.

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