Sequential Read Performance

Our first test of sequential read performance uses short bursts of 128MB, issued as 128kB operations with no queuing. The test averages performance across eight bursts for a total of 1GB of data transferred from a drive containing 16GB of data. Between each burst the drive is given enough idle time to keep the overall duty cycle at 20%.

Burst 128kB Sequential Read (Queue Depth 1)

The burst sequential read performance of the Samsung 860 QVO is generally competitive with mainstream TLC SATA SSDs and is well ahead of the DRAMless Toshiba TR200. The 1TB 860 QVO's score is a bit lower when the drive isn't full because of the timing of the tests: the drive was still flushing the SLC cache in the background when the read test started.

Our test of sustained sequential reads uses queue depths from 1 to 32, with the performance and power scores computed as the average of QD1, QD2 and QD4. Each queue depth is tested for up to one minute or 32GB transferred, from a drive containing 64GB of data. This test is run twice: once with the drive prepared by sequentially writing the test data, and again after the random write test has mixed things up, causing fragmentation inside the SSD that isn't visible to the OS. These two scores represent the two extremes of how the drive would perform under real-world usage, where wear leveling and modifications to some existing data will create some internal fragmentation that degrades performance, but usually not to the extent shown here.

Sustained 128kB Sequential Read

On the longer sequential read test, the 860 QVO continues to get reasonably close to the SATA speed limit when reading data that is contiguous on the flash itself. Where internal fragmentation is caused by writing to the drive randomly, the QVO's read speed suffers much more than for the TLC drives, and the 1TB 860 QVO ends up slightly slower than a mechanical hard drive.

Sustained 128kB Sequential Read (Power Efficiency)
Power Efficiency in MB/s/W Average Power in W

The power efficiency of the 860 QVO is only a little bit lower than the TLC drives for the contiguous data case. When dealing with fragmented data, the QVO is slightly more efficient than the Intel/Micron NVMe QLC drives despite being a bit slower.

The queue depth scaling behavior for the 860 QVO is very typical, with QD1 not quite saturating the SATA link but all higher queue depths hitting close to full speed. The one exception is a slight decrease from the 1TB drive during the final QD32 phase.

Aside from the mild QD32 drop in performance, the sequential read behavior of the 860 QVO doesn't fall outside the normal ranges we've come to expect from TLC drives.

Sequential Write Performance

Our test of sequential write burst performance is structured identically to the sequential read burst performance test save for the direction of the data transfer. Each burst writes 128MB as 128kB operations issued at QD1, for a total of 1GB of data written to a drive containing 16GB of data.

Burst 128kB Sequential Write (Queue Depth 1)

The Samsung 860 QVO handles the burst sequential write test fine when the drive is mostly empty and there's plenty of room in the SLC cache. When the drive is full, the 1TB model's speed suffers somewhat, but is still much faster than the mechanical hard drive or the DRAMless TLC drive.

Our test of sustained sequential writes is structured identically to our sustained sequential read test, save for the direction of the data transfers. Queue depths range from 1 to 32 and each queue depth is tested for up to one minute or 32GB, followed by up to one minute of idle time for the drive to cool off and perform garbage collection. The test is confined to a 64GB span of the drive.

Sustained 128kB Sequential Write

On the longer sequential write test, the SLC cache of the 1TB 860 QVO is not quite enough even when the drive is mostly empty, so it ends up in last place. The 4TB model's SLC cache keeps up with this test and it is as fast as any SATA drive.

Sustained 128kB Sequential Write (Power Efficiency)
Power Efficiency in MB/s/W Average Power in W

The 860 QVO is a bit more power-hungry than the 860 EVO, so the 4TB QVO only takes third place for efficiency among the SATA drives in this bunch. The 1TB QVO has similar efficiency to the faster but more power-hungry 1TB QLC NVMe drives from Intel and Micron.

The 1TB 860 QVO is mostly slow and steady during the sequential write test, while the 4TB model's performance is as good as any other SATA drive.

The 1TB 860 QVO's sequential write behavior sticks out clearly as far slower than typical, but it's not unprecedented: there have been TLC drives this slow, but most of them were much smaller than 1TB. The 4TB model blends in with the crowd much better.

Random Performance Mixed Read/Write Performance


View All Comments

  • stanleyipkiss - Tuesday, November 27, 2018 - link

    Sell me a 8 TB QLC SSD for $400 and I'll bite. That's what QLC is for: moving off of spinning rust and onto SSDs with my bulk storage. Until then, this is useless without MASSIVE price drops. They are trying to milk saps who can't tell the difference between SSDs (i.e. normal consumers) by not dropping prices... yet.

    The race to the bottom for SSDs is coming. The manufacturers are just greedy enough not to want it to happen too soon.

    But give me an 8TB or bigger SSD for $400 and I'll be the first to buy it. I'll even buy two!
  • R0H1T - Tuesday, November 27, 2018 - link

    Yeah no one's selling you 8TB for $400 anytime soon. Aside from the fact that the R&D costs for QLC need to be recuperated first & companies need to reinvest an increasing amount for future development, there's also a point after which it doesn't make sense for the SSD, or NAND, maker to sell these at a loss.

    If you really want something that big, for dirt cheap, try spinners instead.
  • shabby - Tuesday, November 27, 2018 - link

    How will they recoup the price when no one is going to buy this? The evo 860 is cheaper. Reply
  • R0H1T - Tuesday, November 27, 2018 - link

    So you think the 860 QVO will stay at 15c/GB for the rest of it's time on the market or have you not seen high prices at launch, for any other product before this? Reply
  • shabby - Tuesday, November 27, 2018 - link

    Obviously no, but why launch it at this price from the start. Should of launched it at $99 for 1tb that would probably get it some fanfare. Reply
  • R0H1T - Tuesday, November 27, 2018 - link

    Early adopter tax? Samsung is usually the first to launch "one of a kind" products in the retail market & they get the ball rolling for many of the innovations in this industry. The prices would come down sooner if the competitors launch their SATA QLC drives quickly. Reply
  • shabby - Tuesday, November 27, 2018 - link

    I doubt anyone will be rushing to the store to buy these. Reply
  • Ironchef3500 - Wednesday, November 28, 2018 - link

    +1 Reply
  • Jad77 - Wednesday, November 28, 2018 - link

    "I doubt anyone will be rushing to the store to buy these."

    That is the perfect one-line review!
  • moozooh - Tuesday, November 27, 2018 - link

    Yeah, the problem here is that the QVO is not a "one of a kind product"—in every possible aspect and scenario it's either the same as the EVO or worse, sometimes very substantially so, without being substantially cheaper. Right now there is exactly zero reason to choose it over the EVO. In order to compete with it favorably the QVO needs to be at least 25% cheaper to offset the disadvantages. In other words, under 11 c/GB. Until then nobody would be willing to give this inferior product the time of the day. Reply

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