Performance Consistency

Performance consistency tells us a lot about the architecture of these SSDs and how they handle internal defragmentation. The reason we don’t have consistent IO latency with SSD is because inevitably all controllers have to do some amount of defragmentation or garbage collection in order to continue operating at high speeds. When and how an SSD decides to run its defrag or cleanup routines directly impacts the user experience as inconsistent performance results in application slowdowns.

To test IO consistency, we fill a secure erased SSD with sequential data to ensure that all user accessible LBAs have data associated with them. Next we kick off a 4KB random write workload across all LBAs at a queue depth of 32 using incompressible data. The test is run for just over half an hour and we record instantaneous IOPS every second.

We are also testing drives with added over-provisioning by limiting the LBA range. This gives us a look into the drive’s behavior with varying levels of empty space, which is frankly a more realistic approach for client workloads.

Each of the three graphs has its own purpose. The first one is of the whole duration of the test in log scale. The second and third one zoom into the beginning of steady-state operation (t=1400s) but on different scales: the second one uses log scale for easy comparison whereas the third one uses linear scale for better visualization of differences between drives. Click the buttons below each graph to switch the source data.

For more detailed description of the test and why performance consistency matters, read our original Intel SSD DC S3700 article.

  WD Black2 120GB Samsung SSD 840 EVO mSATA 1TB Mushkin Atlas 240GB Intel SSD 525 Plextor M5M
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The area where low cost designs usually fall behind is performance consistency and the JMF667H in the Black2 is no exception. I was actually expecting far worse results, although the JMF667H is certainly one of the worst SATA 6Gbps controllers we've tested lately. The biggest issue is the inability to sustain performance because while the thickest line is at ~5,000 IOPS, the performance is constantly dropping below 1,000 IOPS and even to zero on occasion. Increasing the over-provisioning helps a bit, although no amount of over-provisioning can fix a design issue this deep.

  WD Black2 120GB Samsung SSD 840 EVO mSATA 1TB Mushkin Atlas 240GB Intel SSD 525 Plextor M5M
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  WD Black2 120GB Samsung SSD 840 EVO mSATA 1TB Mushkin Atlas 480GB Intel SSD 525 Plextor M5M
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TRIM Validation

To test TRIM, I first filled all user-accessible LBAs with sequential data and continued with torturing the drive with 4KB random writes (100% LBA, QD=32) for 30 minutes. After the torture I TRIM'ed the drive (quick format in Windows 7/8) and ran HD Tach to make sure TRIM is functional.

Based on our sequential Iometer write test, the write performance should be around 150MB/s after secure erase. It seems that TRIM doesn't work perfectly but performance would likely further recover after some idle time.

The Drive & The Test AnandTech Storage Bench 2013
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  • MrSpadge - Thursday, January 30, 2014 - link

    Yeah, with the current product choices and price point they're effectively betting "People, please don't buy this!" and will probably wonder about low sales at some point. Seagate introduced a 2 TB 2.5" drive with standard 9.5 mm height a few months ago - that's pretty impressive, but might not have enough space left for an mSATA SSD due to it using 3 platters. Reply
  • ImSpartacus - Thursday, January 30, 2014 - link

    For $300, you could easily get a ~500GB SSD.

    I feel like the black2 @ $300 is only useful for people that absolutely need that extra 620GB of storage in a single 2.5" drive.
    Reply
  • hucklongfin - Saturday, February 1, 2014 - link

    I guess I'm old (and I am), but I remember paying $700 for a 70mb drive (Micropolis?) back in the late 80's and not asking too many questions because I assumed it "fell" off the back of a truck.. I put it in my ALR 386 with a 1006 1:1 controller. It was the bomb back in the day. I have a long memory so lot of stuff doesn't seem that expensive to me! Reply
  • Frangelina - Saturday, February 1, 2014 - link

    That's what I did to my 8470p. An M4 256 and a momentus XT500 I bought a year ago at NE for $79 in a caddy for the DVD slot. Reply
  • Tuvok86 - Thursday, February 6, 2014 - link

    This is exactly what I did years ago, upgraded to 128GB ssd and switched the cd drive with the stock 500GB hd.
    This thing would have been great at that time but nowadays, seriously, you can get a 500GB ssd, even preinstalled, even cheaper. Too little, too late.
    Reply
  • philipma1957 - Thursday, February 6, 2014 - link

    price is way too high . 290 for 1.12 tb storage a crucial 960gb ssd is 400 on sale a samsung 1tb ssd is 500 on sale. why pay 290 for a clearly inferior product. Now if it was 250 gb plus 1.5tb for 290 it would make some sense. Reply
  • twtech - Saturday, February 15, 2014 - link

    Even in the case where you need a lot of storage with just one bay, I'd argue that a 1TB SSD would still be a significantly superior option from a performance and power consumption standpoint, and you can buy a Samsung 840 series on Newegg right now for only a couple hundred dollars more. So that even further narrows the target market for this drive. Reply
  • danwat1234 - Wednesday, January 21, 2015 - link

    Now it's only $130 on Newegg!! Reply
  • Aseries - Friday, February 20, 2015 - link

    The real world price of this device is down to $128 at Amazon. Reply
  • tipoo - Thursday, January 30, 2014 - link

    So being a manually managed dual disk, could someone configure this as a Fusion Drive or similar? Reply

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