Performance Consistency

Our performance consistency test explores the extent to which a drive can reliably sustain performance during a long-duration random write test. Specifications for consumer drives typically list peak performance numbers only attainable in ideal conditions. The performance in a worst-case scenario can be drastically different as over the course of a long test drives can run out of spare area, have to start performing garbage collection, and sometimes even reach power or thermal limits.

In addition to an overall decline in performance, a long test can show patterns in how performance varies on shorter timescales. Some drives will exhibit very little variance in performance from second to second, while others will show massive drops in performance during each garbage collection cycle but otherwise maintain good performance, and others show constantly wide variance. If a drive periodically slows to hard drive levels of performance, it may feel slow to use even if its overall average performance is very high.

To maximally stress the drive's controller and force it to perform garbage collection and wear leveling, this test conducts 4kB random writes with a queue depth of 32. The drive is filled before the start of the test, and the test duration is one hour. Any spare area will be exhausted early in the test and by the end of the hour even the largest drives with the most overprovisioning will have reached a steady state. We use the last 400 seconds of the test to score the drive both on steady-state average writes per second and on its performance divided by the standard deviation.

Steady-State 4KB Random Write Performance

Starting with a look at steady-state performance, the 750 EVO is clearly inferior to the 850 EVO, particularly at 250GB. But it outperforms most of the planar TLC competition and the occasional low-end MLC drive.

Steady-State 4KB Random Write Consistency

The high consistency score is a hallmark of Samsung's top-notch controller architecture. The 750 EVO is in an entirely different league from the planar TLC drives.

IOPS over time
25% Over-Provisioning

The 750 EVO's initial burst of high performance is relatively short-lived, but it transitions into a very well-regulated steady state. The gradual performance recovery before a second smaller drop in performance is less pronounced than on the other Samsung drives, but is still present.

With extra overprovisioning, the 750 EVO's steady state shows much looser performance regulation but is still delivering a better worst-case than its competition's best-case.

Steady-State IOPS over time
25% Over-Provisioning

A closer look at the 750 EVO's steady state is pretty boring, with no clear patterns of periodic background maintenance or sporadic outliers.

Introduction, The Drive & The Test AnandTech Storage Bench - The Destroyer
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  • Meteor2 - Saturday, April 23, 2016 - link

    Can't you come up with a more insightful comment, rather than a personal jibe?
  • Eden-K121D - Sunday, April 24, 2016 - link

    His Name Speaks Volumes
  • BrokenCrayons - Monday, April 25, 2016 - link

    Wouldn't embracing the internet mean using offsite storage or streaming content rather than storing it locally?
  • cm2187 - Friday, April 22, 2016 - link

    Any news on Samsung's 4TB SSDs?
  • trparky - Friday, April 22, 2016 - link

    Crap. Does this mean that production of the 850 EVO will stop? God I hope not, the 850 EVO is still a clear winner in my mind.
  • Kristian Vättö - Friday, April 22, 2016 - link

    Absolutely not. The 850 EVO and PRO will continue to be available - the 750 EVO is just a new entry-level addition to the lineup.
  • Coup27 - Friday, April 22, 2016 - link

    What part of the article gave you that impression?
  • trparky - Saturday, April 23, 2016 - link

    I was thinking along the lines of the 750 EVO replacing the 850 EVO in the product lineup. That's something I hope doesn't happen.
  • StrangerGuy - Friday, April 22, 2016 - link

    Enjoyed the bottom to the barrel, cost cutting to the max 768p crappy laptop TN LCDs? Now coming to every future consumer SSDs near you.
  • ingwe - Friday, April 22, 2016 - link

    I'll take a cheap SSD over a shitty 768p panel any day!

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