Mixed Random Performance

Our test of mixed random reads and writes covers mixes varying from pure reads to pure writes at 10% increments. Each mix is tested for up to 1 minute or 32GB of data transferred. The test is conducted with a queue depth of 4, and is limited to a 64GB span of the drive. In between each mix, the drive is given idle time of up to one minute so that the overall duty cycle is 50%.

Mixed 4kB Random Read/Write

The Samsung 860 QVO's performance on the mixed random I/O test is substantially slower than the 860 EVO, but it is not far behind some of the other mainstream TLC drives. Running the test on a full drive does slow the 1TB 860 QVO down significantly, but it remains faster than the DRAMless TLC drive.

Sustained 4kB Mixed Random Read/Write (Power Efficiency)
Power Efficiency in MB/s/W Average Power in W

The power efficiency rankings for the 860 QVO aren't much better than the raw performance rankings. Power consumption is generally a bit higher than the 860 EVO but doesn't vary much with capacity or state of fill, so the efficiency scores are largely reflective of the performance variations.

The 860 QVO starts out with a fairly slow random read speed but steadily speeds up as the workload shifts toward writes, eventually catching up to the 860 EVO. When the test is run on a full drive, the 1TB 860 QVO runs out of SLC cache in the final few phases of the test and slows down instead of continuing to speed up.

Mixed Sequential Performance

Our test of mixed sequential reads and writes differs from the mixed random I/O test by performing 128kB sequential accesses rather than 4kB accesses at random locations, and the sequential test is conducted at queue depth 1. The range of mixes tested is the same, and the timing and limits on data transfers are also the same as above.

Mixed 128kB Sequential Read/Write

The 4TB 860 QVO handles the mixed sequential I/O test well, but the 1TB model ends up slightly slower than the DRAMless TLC drive and well behind the mainstream TLC drives.

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

The power efficiency scores vary more among the SATA drives than the raw performance scores, so the 860 EVO and Toshiba TR200 stand out as particularly efficient while the 860 QVO 4TB is merely average and the 1TB model is struggling a bit.

Both capacities of the 860 QVO offer decent performance at either end of the test with pure reads or pure writes, and they are unsurprisingly at their worst with the more write-heavy mixes. The 1TB 860 QVO loses far more performance across the first two thirds of the test, but catches back up with the 4TB model at the end.

Sequential Performance Power Management


View All Comments

  • Morawka - Wednesday, November 28, 2018 - link

    I just had 2 Samsung QLC 3 bit drives die this year alone. They were less than 1.5 year old. I'm never buying Samsung's EVO line again. It will be Pro from here on out. 4 bit drives will fail even faster. Reply
  • Makaveli - Wednesday, November 28, 2018 - link

    Which model evo's were those Morawka?

    And how many writes did they see? what kind of environment did you have them in?
  • stephenbrooks - Wednesday, November 28, 2018 - link

    I was starting to get excited about 2TB for $300 but then I looked up 2TB HDDs and they're about $60. Still a huge price differential especially as I usually want at least one extra drive for nightly backups, although perhaps the backup drive could be the HDD? Reply
  • Lolimaster - Thursday, November 29, 2018 - link

    Even with the right capacities for a QLC price is similar or worse than current TLC.

    Samsunf 860 EVO 1TB $127

    For QLC to make sense it should HALF of a TLC else is a ripoff.
  • s.yu - Friday, November 30, 2018 - link

    What's the point of trying to pronounce it? It's just Q-V-O! Reply
  • araczynski - Friday, November 30, 2018 - link

    so basically next black friday these should be half price and the 4tb might be worthy of consideration as a Steam drive. Reply
  • thomas-hrb - Friday, November 30, 2018 - link

    $149.99 launch price is encouraging even if it is currently more than the 860evo. The 860evo launched for over $300 (closer to $330) and is now $139. If the qvo follows this pattern we can look forward to sub $65 for the 1tb qvo and maybe even $250 for 4tb. Reply
  • Ankou - Friday, November 30, 2018 - link

    I think these QLC drives are a bad idea especially in the way they're being marketed. I'm not even talking about performance, the speed reduction I could live with. However, they're orders of magnitude worse in P/E cycles, retention, and endurance. These manufacturers know this and they're preying on the lack of education and focusing on price. Even so far as advertising these drives (this one in particular) as using 4 bit MLC memory (which 4 bit MLC is *always* QLC) implying that it is on safer MLC memory:


    That is completely a scummy marketing/PR way of doing business.
  • s.yu - Saturday, December 1, 2018 - link

    The fundamental issue is that 2-bit MLC should have been accurately named DLC in the first place, it's not like somebody's gonna mix that up with downloadable content. Reply
  • 0ldman79 - Saturday, December 15, 2018 - link

    Could we get some numbers from some mechanical drives, WD or Seagate 1TB or 2TB, in comparison to the slower QLC drives?

    I'd like to see how they hold up against the QLC in random and sustained reads/writes. The latency might be the deciding factor even though I've got some mechanical drives that can beat them on sustained reads/writes.

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