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Results: Random Performance

SanDisk A110 PCIe SSD: Armed With The New M.2 Edge Connector
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We turn to Iometer as our synthetic metric of choice for testing 4 KB random performance. Technically, "random" translates to a consecutive access that occurs more than one sector away. On a mechanical hard disk, this can lead to significant latencies that hammer performance. Spinning media simply handles sequential accesses much better than random ones, since the heads don't have to be physically repositioned. With SSDs, the random/sequential access distinction is much less relevant. Data are put wherever the controller wants it, so the idea that the operating system sees one piece of information next to another is mostly just an illusion.

4 KB Random Reads

Testing the performance of SSDs often emphasizes 4 KB random reads, and for good reason. Most system accesses are both small and random. Moreover, read performance is arguably more important than writes when you're talking about typical client workloads.

SanDisk's A110 behaves a lot like the Extreme II. And that's logical, considering the similarities between both drives. Small random accesses are dependent on flash, controller, and firmware performance; they aren't bottlenecked by SATA. Samsung's 840 Pro approaches 100,000 4 KB read IOPS, but that's still just around 400 MB/s. The A110 manages to score a win at a queue depth of 32, just inching past 100,000 IOPS.

This M.2-based SSD is actually rated for up to 115,000 IOPS. Keep in mind that we're not using a platform with native support for it, though. Performance may vary due to our adapter. In production, we'd expect a notebook equipped with the A110 to fare similarly or better.

4 KB Random Writes

Random write performance is also exceptionally important, without question. Early SSDs didn't do well in this discipline, seizing up even in lightweight workloads. Newer SSDs wield more than 100x the performance of drives from 2007, but there's a point of diminishing returns in client environments. When you swap a hard drive out for solid-state storage, your experience improves. Load times, boot times, and system responsiveness all get better. If called upon, your SSD-equipped system could handle a lot more I/O than the spinning media you had in there before. With consumer workloads, it's more about getting to those operations faster, not necessarily handling more of them.

This is the first time we've questioned the A110's performance (or at least, it would be if we hadn't seen the same behavior twice before). SanDisk's nCache technology isn't designed to be peppered over a large LBA space for long periods of time. Because that's what we're doing, performance appears lower. Still, the drive offers up over 60,000 IOPS every second at higher queue depths.

Here's a break-down of the maximum observed 4 KB sequential read and write performance with Iometer:

The highest 4 KB reads we've tested come from the A110. It'd fare even better if we tested 4 KB random writes differently. The order the drives appear in our chart is determined by maximum combined read and write performance, which is frankly an arbitrary (but still valid) way of sorting.

Write Saturation

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

Through the first 600 minutes writing at a queue depth of 32, SanDisk's SSD takes its sweet time settling in at a steady state. That's in part due to the fact that the A110 doesn't do so well writing against the entire 256 GB LBA space, so that initial high-speed fill doesn't quite materialize.

When we break out a time slice of the 10 hours we're showing, illustrating the write I/O in more detail, it's clear that the A110 does well, even without additional over-provisioning (which would leave more room to run garbage collection algorithms, lending to higher transactional performance with every block filled).

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  • 0 Hide
    Mike Friesen , September 5, 2013 10:03 PM
    Awesome new stuff. Can't wait to see if this drive actually uses the full potential of the M2, and if Samsung or OCZ can one-up them.
  • 5 Hide
    cryan , September 5, 2013 10:31 PM
    Quote:
    Awesome new stuff. Can't wait to see if this drive actually uses the full potential of the M2, and if Samsung or OCZ can one-up them.


    Samsung actually has some pretty awesome M.2 PCIe action going on. We're trying to get our hands on everything, so stay tuned.


    Regards,
    Christopher Ryan

  • 0 Hide
    radiovan , September 5, 2013 10:32 PM
    It will be nice to see vendors implement the NVMe connectors in the desktop mobo's, which in turn will redefine case design, as less storage space will be required for storage. I am aware that the initial intent is to direct these at the mobile market, but desktops can benefit as well.
  • 2 Hide
    cryan , September 5, 2013 11:08 PM
    Quote:
    It will be nice to see vendors implement the NVMe connectors in the desktop mobo's, which in turn will redefine case design, as less storage space will be required for storage. I am aware that the initial intent is to direct these at the mobile market, but desktops can benefit as well.


    You'll really see NVMe take off on the desktop with the move towards SATA Express. A SSD on SATA Express will leverage NVMe and two PCIe Gen 3 lanes. Though some motherboards will (and already do) have M.2 connectors, M.2 really makes more sense in mobile applications. M.2 will only get traction on the desktop insofar as it will begin to replace mSATA. Tons of mainboards, especially smaller form factor products embrace mSATA, and moving to M.2 is a natural transition. However, M.2 drives are hard to find right now, and we really won't see a plethora of options until next year.

    Regards,
    Christopher Ryan
  • 1 Hide
    nekromobo , September 6, 2013 12:50 AM
    I got M.2 toshiba ssd in my Sony Vaio Pro 13.. review that?

    and it should have samsung M.2 in some countries..
  • 2 Hide
    CaedenV , September 6, 2013 8:59 AM
    I may no longer have motivation to upgrade my system based on CPU specs, but with DDR4, M.2, new restive storage based SSDs, and better chipset features I will still have enough reason to upgrade in a year or two.
  • 0 Hide
    jimmysmitty , September 6, 2013 9:07 AM
    Quote:
    Quote:
    It will be nice to see vendors implement the NVMe connectors in the desktop mobo's, which in turn will redefine case design, as less storage space will be required for storage. I am aware that the initial intent is to direct these at the mobile market, but desktops can benefit as well.


    You'll really see NVMe take off on the desktop with the move towards SATA Express. A SSD on SATA Express will leverage NVMe and two PCIe Gen 3 lanes. Though some motherboards will (and already do) have M.2 connectors, M.2 really makes more sense in mobile applications. M.2 will only get traction on the desktop insofar as it will begin to replace mSATA. Tons of mainboards, especially smaller form factor products embrace mSATA, and moving to M.2 is a natural transition. However, M.2 drives are hard to find right now, and we really won't see a plethora of options until next year.

    Regards,
    Christopher Ryan


    That's what I was thinking. SATA Express is going to be fast enough for now as I have used PCIe SSDs before (OCZ Revo based drive) and compared to my 520 its hard to notice a difference, especially since there are other bottlenecks stopping it from being able to utilize that bandwidth.

    This will be great for ultra portable systems though and ITX systems.
  • 2 Hide
    cryan , September 6, 2013 10:52 AM
    Quote:
    I got M.2 toshiba ssd in my Sony Vaio Pro 13.. review that?

    and it should have samsung M.2 in some countries..


    Absolutely... just send it my way and consider it done.

    Regards,
    Christopher Ryan


  • 0 Hide
    m32 , September 6, 2013 12:11 PM
    Christopher Ryan, I'll take this off of your hands.

    Regards,
    m32
  • 0 Hide
    mikeangs2004 , September 6, 2013 7:19 PM
    will there be RAID or SLI/CFX for PCIe based SSD's?
    I don't think so b/c it's already way above 6G limit.
  • 0 Hide
    markhahn , September 7, 2013 11:04 AM
    the power numbers don't make a lot of sense. I suspect either the pcie interface is being kept in a high-power mode (plls running, etc) or else your molex is supplying power to other stuff on the board. (there must be a dc-dc regulator on the auxiliary card, since molex provides only 12,5.)
  • 0 Hide
    cryan , September 7, 2013 6:04 PM
    Quote:
    the power numbers don't make a lot of sense. I suspect either the pcie interface is being kept in a high-power mode (plls running, etc) or else your molex is supplying power to other stuff on the board. (there must be a dc-dc regulator on the auxiliary card, since molex provides only 12,5.)


    This is almost certainly true. I mean, we know it uses DC to DC to step the 5v down to 3.3v. But oddly, SanDisk rates the max write power consumption at 5.5w, and I could only get it max at 3.5w. Of course, it also possesses a deep slumber state, but that's contingent on having a L1.0 PCIe endpoint, and that hasn't even been ratified yet by PCI-SIG.

    So definitely take the power consumption results with a grain of salt. There are challenges to testing this drive in this way.


    Regards,
    Christopher Ryan
  • 0 Hide
    cryan , September 7, 2013 7:16 PM
    Quote:
    will there be RAID or SLI/CFX for PCIe based SSD's?
    I don't think so b/c it's already way above 6G limit.


    If you happened to have the ability to run two+ PCIe SSDs, M.2 or otherwise, you can always soft-raid them. There are reasons why you'd want to avoid such a setup, but it'd totally work. Intel's 910 PCIe SSD shows 2 or 4 drives to the OS and then they can be soft-raided from there, for instance.


    Regards,
    Christopher Ryan

  • 0 Hide
    abbadon_34 , September 8, 2013 4:31 PM
    what command line switches were use in robocopy?
  • 0 Hide
    mikeangs2004 , September 9, 2013 5:31 PM
    Is there TRIM/garbage collection?
  • 0 Hide
    Dax corrin , September 10, 2013 11:33 AM
    Awesome stuff, wish I could afford it.
  • 0 Hide
    Blaise170 , September 15, 2013 9:44 AM
    It seems like new progress is being made in the field of NAND every day. I can't wait until you can get high capacity drives for around the same price as HDDs, but I've heard that even as late as 2017 SSD storage will only have a 33% share.
  • 0 Hide
    ryyple , October 4, 2013 12:20 AM
    I'm a complete novice to all this stuff, yet I have a few questions that maybe someone can answer.

    Are these M2 devices still considered SATA drives?
    Using a PCIe (or other) interface for the M2 how could you clone these devices?
    Can these devices then be cloned using a standard HDD duplicator?
    Is there such a thing as a M2 "adapter" that plugs into the above duplicator?

    Thanks for your response.
  • 0 Hide
    tpidner17 , November 12, 2013 7:22 PM
    Christopher,

    On page four of this review, in the maximum 4kb speed chart, it says "in MB/s [higher is better]." However, shouldn't that refer to the fact that it is measuring max IOps, rather than write speed? It seems like a type to me, so I wanted to let you know.