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

Right from the start we see a substantial improvement of the SM2258 over SM2256, as steady-state random write speed has increased by 37%. This puts the Intel 540s well ahead of any other planar TLC drive and ahead of a few low-end MLC drives as well.

Steady-State 4KB Random Write Consistency

While the average random write speed has improved, the consistency is a bit worse and the Intel 540s scores in the bottom tier of drives. Phison's most recent generation of TLC drives managed to deliver very consistent steady state performance, but Silicon Motion still has a lot of room for improvement here.

IOPS over time
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25% Over-Provisioning

The consistency of the 540s was clearly poor even before the transition to steady state, but during that early phase of the test it delivered twice the IOPS of the ADATA SP550.

Steady-State IOPS over time
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25% Over-Provisioning

Once in steady state, the 540s performance mostly stays slightly above the SP550. Both drives have frequent outliers beyond their band of usual performance, and the outliers are almost all in the direction of better performance. The Intel drive's outliers hit some much higher peaks than the ADATA SP550, suggesting that the new SM2258 controller may have significantly improved performance on bursty workloads.

Introduction AnandTech Storage Bench - The Destroyer
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  • redzo - Thursday, June 23, 2016 - link

    About the same price as a 850 EVO. The 540s is not worthy of your $$. Reply
  • Anato - Thursday, June 23, 2016 - link

    Why this is 540, not 340 or even 140? Reply
  • BurntMyBacon - Friday, June 24, 2016 - link

    Apparently, their 300 series has fallen off of their roadmap. Someone please link me to a roadmap that counters this statement. Reply
  • pwil - Wednesday, July 27, 2016 - link

    Because 140 would have 1y warranty, and 340 - 3y warranty. Reply
  • nismotigerwvu - Thursday, June 23, 2016 - link

    The idea of Intel, owner of the most advanced foundries on the planet, buying chips from the open market is oddly humorous to me. I understand why, and honestly it makes logical sense, but it's still an interesting quirk in an industry where quirkiness has mostly vanished. Reply
  • bloodinmyveins - Thursday, June 23, 2016 - link

    Why is it so hard to dethrone Samsung 850 EVO and PRO? :( Reply
  • redzo - Thursday, June 23, 2016 - link

    They've just designed a product and are 100% sure that they are going to sell it overpriced based on brand name only. It's business. Reply
  • Vlad_Da_Great - Thursday, June 23, 2016 - link

    That was a bummer. I bought that with the notion that inside was Intel parts. I guess, they are trying to bang on their name now. 540s has been great so far, but I could have saved about $20 for the 120GB, I bought. AnandTech you are late! Reply
  • cm2187 - Thursday, June 23, 2016 - link

    With Samsung about to introduce 4TB SSDs, a 1TB max size seems to be behind... Reply
  • Ej24 - Thursday, June 23, 2016 - link

    Wow. Not only would I not purchase one of these, but I'm now convinced I need to buy several mx200's as it seems crucial isn't going to release another MLC drive. TLC simply doesn't impress me. The bx200 I put in my mother-in-law's pc was a disaster (granted its a worst case scenario). It's enough to demonstrate the shortcomings of tlc though. They're only able to make up for it with black magic and sophisticated controllers. No thank you. Reply

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