Advanced Synthetic Tests

Our benchmark suite includes a variety of tests that are less about replicating any real-world IO patterns, and more about exposing the inner workings of a drive with narrowly-focused tests. Many of these tests will show exaggerated differences between drives, and for the most part that should not be taken as a sign that one drive will be drastically faster for real-world usage. These tests are about satisfying curiosity, and are not good measures of overall drive performance. For more details, please see the overview of our 2021 Consumer SSD Benchmark Suite.

Whole-Drive Sequential Fill

Pass 1
Pass 2

Some of our other tests have shown a few signs that the 870 EVO's write performance can drop when the SLC cache runs out, but this straightforward sequential write pass over the entire drive doesn't reveal any such behavior. The 870 EVO's sequential write performance is extremely consistent, even on the second write pass.

Sustained 128kB Sequential Write (Power Efficiency)
Average Throughput for last 16 GB Overall Average Throughput

Due to the excellent performance consistency, the Samsung 870 EVOs edge out the other SATA drives with marginally higher average sequential write speeds. The entry-level NVMe drives end up much worse off than the mainstream SATA drives once their caches run out, but the more mainstream NVMe drive blows them all away.


Working Set Size

As expected, the Samsung 870 EVO's random read performance shows basically no variation across a range of working set sizes, and that read performance is at least a little bit faster than any of the other SATA drives or the entry-level NVMe drives.


Performance vs Block Sizes

Random Read
Random Write
Sequential Read
Sequential Write

There are no particular surprises in how the Samsung 870 EVO handles IOs of different block sizes. Unlike some drives, it has no trouble with sub-4kB IOs. It offers moderate improvements over the 860 EVO for mid-sized random reads (up to about 128kB). The one negative is that for writes we again see more inconsistency from the 870 EVO than the 860 EVO when testing an 80% full drive. The simple whole-drive sequential write test may not have been able to reveal any SLC caching troubles, but it does seem clear that the caching behavior has some performance regressions for more complicated workloads on a drive that's more well-used—though it's still unlikely to matter for any typical real-world consumer workload.

Synthetic Tests: Basic IO Patterns Mixed IO Performance and Idle Power Management


View All Comments

  • Tomatotech - Wednesday, February 17, 2021 - link

    These SATA circuit board PCBs are really tiny. I’ve sometimes wondered about removing the PCB from the drive and just plugging it direct into the motherboard SATA socket, no cable or drive case needed. This wouldn’t work out of the box as I think the motherboard port and the drive’s port are both the same gender.

    So this would need 1) a small gender changer intermediary, and 2) a way to get the power cable in there as well. Depending on the orientation of the motherboard SATA port, there might be space next to it for the power cable.
  • Tomatotech - Wednesday, February 17, 2021 - link

    The advantages would be fewer cables and less space taken in small cases. Reply
  • Tomatotech - Wednesday, February 17, 2021 - link

    If SATA drive manufacturers added a secondary power port at the top of the PCB (which they won’t do) and included a small cheap gender changer for the data port, this could become a feasible life extender for using SATA in small or crowded cases. Reply
  • npz - Wednesday, February 17, 2021 - link

    See SATA DOM:
  • npz - Wednesday, February 17, 2021 - link

    Very limited in capacity of course, primarily used as boot drives Reply
  • Tomatotech - Wednesday, February 17, 2021 - link

    I saw that a year or two ago, very neat idea, a small SATA circuit board that sits on top of the motherboard SATA port. Available in sizes up to 128GB.

    Still seems to require a special SATA port and special provision in the motherboard BIOS - possibly to provide a bit of bus power inside the SATA port - so it’s very much a Supermicro-only thing.

    I see no reason why that couldn’t become a new SATA port standard - the Supermicro port is backward compatible with standard SATA drives - and sizes 1TB+ should be possible now.

    But bah it’s probably too late for that now even though millions of motherboards are still being manufactured with SATA ports.
  • Qasar - Wednesday, February 17, 2021 - link

    " I’ve sometimes wondered about removing the PCB from the drive and just plugging it direct into the motherboard SATA socket,"

    is that what nvme physically is ? :-)
  • Gigaplex - Wednesday, February 17, 2021 - link

    No, NVMe is a protocol. You're thinking of M.2, which doesn't have to use NVMe. There are actually many M.2 drives that use the SATA protocol. Reply
  • Gigaplex - Wednesday, February 17, 2021 - link

    You've basically just described M.2 SATA mode. Reply
  • Lord of the Bored - Thursday, February 18, 2021 - link

    Funnily enough, that exists as a product already. Search for "disk on module".
    While more commonly known for the older IDE interface, SATA versions do exist.

    You could, of course, recreate it with an off-the-shelf SATA drive, a screwdriver, and a light touch of solder.

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