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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  • Shadow7037932 - Friday, April 22, 2016 - link

    The prices aren't competitive. The Ultra II in particular tends to go on sale rather often for around $50.
  • Shadow7037932 - Friday, April 22, 2016 - link

    Also, if it's anything like the price drop we saw with the 850 EVOs, this could drop down to ~$50 or so in a few months I think.
  • barleyguy - Friday, April 22, 2016 - link

    This drive hasn't been out long enough to know what price it will go on sale for. So I consider any comments on pricing pretty irrelevant.

    Outside of that, there are only 3 brands of SSD I trust my data to, which is Intel, Crucial/Micron, and Samsung. I'll pay more for those 3 brands than I will other brands, because of reliability.
  • AkulaClass - Friday, April 22, 2016 - link

    As 250GB low cost I would grab a SanDisk Ultra II.
  • barleyguy - Friday, April 22, 2016 - link

    8 of the 48 reviews of that drive on NewEgg are "worked great until it died in a month and I lost my data". As I said in another post, Intel, Crucial, and Samsung are IMO on a different tier of reliability than everybody else.
  • Shadow7037932 - Saturday, April 23, 2016 - link

    I like how you're saying Samsung there without considering the issues they've had with the 840. Out of all three you mentioned, only Intel has had solid SSDs since the first gen.
  • barleyguy - Saturday, April 23, 2016 - link

    I actually own an 840 Evo in my daughter's laptop. The issues with it never involved data loss or "early death", only degraded performance. Even in its degraded performance mode it still feels faster than a hard drive. And the patches they issued to "fix" it work pretty well to restore it back to SSD-like performance.

    So, in short, I still trust Samsung on the SSD front way more than Sandisk.

    Though I don't disagree that Intel makes excellent SSDs. They're the way to go for a "critical main desktop" type application.
  • andrewaggb - Sunday, April 24, 2016 - link

    I was going to say that as well. I have an 840 evo in my machine and I haven't lost any data. I regret purchasing it... but it works. The only SSD I've had die so far was a Kingston V100. Still have a couple intel 320 series ssd's running strong, a couple sandisk ones (don't recall the model numbers) that are working and a crucial M500 that is working.
  • Dwedit - Sunday, April 24, 2016 - link

    I had the old Intel X25-M, and it had a catastrophic failure where the disk name changed to "BAD CONTEXT" and size changed to 8MB.
  • K_Space - Wednesday, April 27, 2016 - link

    X25-M (version 2) still going strong here just not as a main drive since 80Gb is puny. I have both SD Ultra II (960Gb) and 2x Extreme Pro (480Gb) going with no problems. The Extreme Pro was purchased straight after Anadtech glowing review particularly with its 10 years warranty. Not sure what the warranty is for the Ultra II but wouldn't be surprised if its 5+. For every review that says: my SSD died, you'll get a "my SSD is alive & well" so take em with a pinch of salt. It all depends on usage scenario and user expertise and we know how variable that can be.

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