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 ADATA SX8200 Pro and HP EX950 provide top-tier performance on our mixed random I/O test, just shy of the Samsung 970 EVO Plus. The 2TB EX950 has almost identical overall performance to the 1TB models.

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

The power efficiency of the ADATA SX8200 Pro isn't quite as good as the Toshiba XG6 or WD Black SN750, but it's well ahead of the rest of the flash-based SSDs, including the HP EX950.

Compared to their predecessors and most of the competition, the SX8200 Pro and EX950 offer better performance during the read-heavy half of the test. The 970 EVO Plus pulls ahead during the write-heavy half of the test, which is generally faster anyways since write operations can be cached and combined. The Toshiba XG6 and WD Black SN750 that are more efficient than the SX8200 Pro are slower during every phase of the test except for the final segment with pure writes.

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 SM2262EN drives provide great performance on the mixed sequential I/O test, but the Samsung 970 EVO Plus maintains a clear lead, and the 2TB HP EX950 is back to being slower than the 1TB models.

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

The 1TB ADATA SX8200 Pro just barely provides top-tier power efficiency on the mixed sequential I/O test, but the handful of drives that score better include most of the important competition: the latest from Samsung, WD, Toshiba and Phison.

The 2TB HP EX950 is slower than the 1TB model throughout the test, except for the pure read and write segments at either end. The 1TB SX8200 Pro and EX950 outperform their predecessors by an increasingly large margin as the workload becomes more write-heavy. The Samsung 970 EVO Plus that turns in the fastest overall performance runs up the score during the read-heavy half of the test but is no faster than the SM2262EN drives during the write-heavy half.

Sequential Performance Power Management
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  • cassiohui - Thursday, February 7, 2019 - link

    Hi Billy, just wondering, why is the 970 pro not in the graphs when even the 900p is?
  • Death666Angel - Thursday, February 7, 2019 - link

    They have stated on Twitter and in the comments before that they did not receive a 970 Pro review sample.
  • cassiohui - Thursday, February 7, 2019 - link

    960 pro maybe?
  • mapesdhs - Thursday, February 7, 2019 - link

    Pity they don't just buy them in themselves to do the tests anyway. I'd put more faith in data that
    hasn't come from free samples. :)
  • Billy Tallis - Thursday, February 7, 2019 - link

    CPU, GPU and DRAM vendors can in theory sample chips that will overclock better than the average retail item, but there's no easy way for SSD vendors to cheat on performance with careful sampling. And the number of drives that don't survive my testing strongly suggests that they aren't doing any sort of extra QA before sending samples to me.
  • jahid - Thursday, February 7, 2019 - link

    Thanks for your valuable writing. HP some model availble in https://www.startech.com.bd/component/SSD-Hard-Dis...
  • ballsystemlord - Thursday, February 7, 2019 - link

    Well, I will not be purchasing an EX950. That is for sure. I'm bound to run the SLC down quite a bit and then performance will tank.
  • KAlmquist - Sunday, February 10, 2019 - link

    These drives are mostly of interest to people who need odd sized drives. For example, if you need a 600GB drive, you probably have to buy a 1TB drive and only use 600GB of it. Either of the 1TB drives should perform reasonably in this scenario. You might still have to tweak the power saving settings to avoid putting the drive to sleep too frequently (due to the huge wakeup time), but the active idle power is less that one watt.
  • dromoxen - Wednesday, February 20, 2019 - link

    For me , anything over 500Gb is going to be used for mass storage, so HDD rulez. But ssd would be better on speed, noise and (possibly) reliability. I dont need ultra speeds, just something cheap enough, and faster than HDD. A long way off, still .
    Why couldn't ADATA offer two versions of the drive, or at least two firmwares, one for Boy racers, one for commercial use? if you can get a chandelier on your ram sticks ....well?
  • upvts - Monday, July 29, 2019 - link

    How full is full? 100%? And is there a noticeable cliff in the performance, or is there a general decline? Or both (gradual decline in performance until the drives are filled to some threshold amount, after which the performance drops off a cliff)? If we were to leave enough space empty on the drive, could we avoid this hypothetical cliff?

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