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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  • Sn3akr - Monday, April 25, 2016 - link

    8$ is just too little of a difference and will not make a difference in a build as such.. I only see this as being implemented in finished machines from manufacturers, so that they can pop another 8$ in their pocket. Aftermarket.. Doubt it will sell a lot.
    Maybe i would use it in a HTPC, since it's not something that requires a lot of R/W operations once it's booted up
  • slowdemon21 - Thursday, April 28, 2016 - link

    I noticed PNY & OCZ BENCHED IN THE MIDDLE, Sammy on the bottom [loser]
  • Ahmad kassem - Sunday, May 1, 2016 - link

    Is it ok to make more than one partition on this ssd or any other ssd?
  • wayneclaassen - Thursday, May 5, 2016 - link

    Well I needless to say I found the Samsung EVO 250GIG extremely reliable although it is a bit expensive, but for anyone that mostly run high performance graphics this price tag shouldn't be a big problem.
  • Bulat Ziganshin - Saturday, May 7, 2016 - link

    1. 750 may be a hit for developing markets. in particular i've seen 750 reviews on russian sites much earlier than here:

    2. Can you please add to your reviews checks of gc/trim effect and slc cache size as in the section
  • eduard.fisic - Sunday, June 5, 2016 - link

    Billy, when you guys run the benchmarks, are the Samsung Evo drives run with RAPID Mode on or off? Just out of curiosity, as I am looking to buy the 850 Evo and I'd like to know if I can expect this sort of performance without having to turn on RAPID Mode. Thanks!
  • jason_brody - Thursday, July 7, 2016 - link

    Can anyone help if I should go with this SSD or 850 series for my Dell E6500?
  • elzafir - Tuesday, April 11, 2017 - link

    The 250GB 840 EVO is $15 cheaper where I live compared to the 750 EVO of the same size. Which one should I get?
  • Manisthisunreal - Friday, October 13, 2017 - link

    Notice because of all the fatmouths saying they'll "wait until it is cheaper" the industry has now colluded to up the prices and make up some bs excuses of "low demand" "commodity trader speculation on minerals". Yes we can blame stock traders for a lot of things like high oil prices, high wheat and other food goods prices but come on I smell something fishy. I was about to buy a 250gb Samsung SSD on black Friday for $60 almost two years ago when some idiot shopper woman decided to merge into me when I was on my way home from work leading to a 15 month nightmare. I never did make it out to get my ssd. Fast forward almost 2 years later and they've doubled in price. I really wanted that.

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