Mixed Random Read/Write Performance

Mixed read/write tests are also a new addition to our test suite. In real world applications a significant portion of workloads are mixed, meaning that there are both read and write IOs. Our Storage Bench benchmarks already illustrate mixed workloads by being based on actual real world IO traces, but until now we haven't had a proper synthetic way to measure mixed performance. 

The benchmark is divided into two tests. The first one tests mixed performance with 4KB random IOs at six different read/write distributions starting at 100% reads and adding 20% of writes in each phase. Because we are dealing with a mixed workload that contains reads, the drive is first filled with 128KB sequential data to ensure valid results. Similarly, because the IO pattern is random, I've limited the LBA span to 16GB to ensure that the results aren't affected by IO consistency. The queue depth of the 4KB random test is three.

Again, for the sake of readability, I provide both an average based bar graph as well as a line graph with the full data on it. The bar graph represents an average of all six read/write distribution data rates for quick comparison, whereas the line graph includes a separate data point for each tested distribution. 

Iometer - Mixed 4KB Random Read/Write

The SSD 750 does very well in mixed random workloads, especially when compared to the SM951 that is slower than most high-end SATA drives. The performance scales quite nicely as the portion of writes is increased.

Intel SSD 750 1.2TB (PCIe 3.0 x4 - NVMe)

 

Mixed Sequential Read/Write Performance

The sequential mixed workload tests are also tested with a full drive, but I've not limited the LBA range as that's not needed with sequential data patterns. The queue depth for the tests is one.

Iometer - Mixed 128KB Sequential Read/Write

In mixed sequential workloads, however, the SSD 750 and SM951 are practically indentical. Both deliver excellent performance at 100% reads and writes, but the performance does drop significantly once reads and writes are mixed. Even with the drop, the two push out 400MB/s whereas most SATA drives manage ~200MB/s, so PCIe certainly has a big advantage here.

Intel SSD 750 1.2TB (PCIe 3.0 x4 - NVMe)
Sequential Performance ATTO, AS-SSD & TRIM Validation
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  • KAlmquist - Thursday, April 2, 2015 - link

    It's too bad that Anandtech didn't benchmark the 400 GB model, since that's the one most people are going to be most interested in buying. I assume that it's a case of Intel not making the 400 GB model available for review, rather than Anandtech deciding not to review it.
  • jwilliams4200 - Thursday, April 2, 2015 - link

    Agreed, the 400 GB model is more interesting to consumers.

    Also, I hope that if Anandtech does test the 400GB model, that they re-run the tests of the comparison SSDs so that the competitors are overprovisioned to 400GB usable capacity (from 512GB or whatever nominal capacity). That is the only reasonable way to compare, since anyone who wants high sustained performance and is willing to try a drive with only 400GB to achieve it would obviously be willing to overprovision, for example, a 512GB Samsung 850 Pro to only 400GB usable to achieve higher sustained performance.
  • Kristian Vättö - Thursday, April 2, 2015 - link

    That is something that I've had on my mind for a while now and I even have a way to do it now (the Storage Bench traces are a bit tricky since they are run on a raw drive, but thankfully I found an hdparm command for limiting the far LBA count). The only issue is time because it takes roughly two days to test one drive through the 2015 suite, so I may be include a drive or two as comparison points but I definitely can't test all drives with added OP.
  • Kristian Vättö - Thursday, April 2, 2015 - link

    Not far LBA count, but raw LBA count, obviously :)
  • Stahn Aileron - Friday, April 3, 2015 - link

    Honestly, I'd rather have AnandTech test drives and components as-is ("stock" from the manufacturer) and publish those results rather than spend time doing tests on non-standard, customized configurations. Let the customers do that if they truly need that type of set-up or leave it to integrators/specialists.

    As far as I know, most customers of a product just want to use it immediately right of the box, no mucking with special settings. Most products are advertised that way as well.

    Really, just test the product(s) as advertised/intended by the manufacturer first and foremost to see if it matches their claims and properly serves the target userbase. Specialty cases should only be done if that is actively advertised as a feature, there is truly high interest, something makes you curious, and/or you have the time.
  • jwilliams4200 - Friday, April 3, 2015 - link

    If this were a review site for the totally clueless, then you might have a point. But anandtech has always catered to enthusiasts and those who either already know a lot about how computer equipment works, or who want to learn.

    The target audience for this site would certainly consider something as simple as overprovisioning an SSD if it could significantly increase performance and/or achieve similar performance at lower cost relative to another product. So it makes sense to test SSDs configured for similar capacity or performance rather than just "stock" configuration. Anyone can take an SSD and run a few benchmarks. It takes a site as good as anandtech to go more in-depth and consider how SSDs are actually likely to be used and then present useful tests to its readers.
  • Kristian Vättö - Thursday, April 2, 2015 - link

    That is correct. I always ask for all capacities, but in this case Intel decided to sample all media with only 1.2TB samples. I've asked for a 400GB, though, and will review it as soon as I get it.
  • Mr Alpha - Thursday, April 2, 2015 - link

    Has anyone managed to find this mythological list of compatible motherboards?
  • Kristian Vättö - Thursday, April 2, 2015 - link

    I just asked Intel and will provide a link as soon as I get one. Looks like it's not up yet as they didn't have an answer right away.
  • tstones - Thursday, April 2, 2015 - link

    Older chipsets like z77 and z87 will support NVMe?

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