WD_Black SN850 PCIe 4.0 NVMe SSD Review – Vying For That Top Spot


The SSD Review uses PCMark 8’s Storage test suite to create testing scenarios that might be used in the typical user experience. With 10 traces recorded from Adobe Creative Suite, Microsoft Office and a selection of popular games, it covers some of the most popular light to heavy workloads. Unlike synthetic storage tests, the PCMark 8 Storage benchmark highlights real-world performance differences between storage devices. After an initial break-in cycle and three rounds of the testing, we are given a file score and bandwidth amount. The higher the score/bandwidth, the better the drive performs.

The SN850 provided performance in PCMark 8 somewhat in the area that we might have expected, although we had hoped it might hit just a bit higher.



For our Real World File Transfer Comparison of the world’s top M.2 NVMe SSDs, we have included several of the top Gen 4 SSDs tested to date, to include the Samsung 980 Ppro, Corsair MP600, Seagate FireCuda 520, Sabrent Rocket. and the Silicon Power US70. This test is conducted through the transfer of data from one spot on the test drive to another to give us the truest of transfer speed results for that device.


The WD_Black Sn850 Gen 4 NVMe SSD performed as we had never seen before in our True Data Transfer Comparison.  It actually cut the transfer time of the OS file sample in half, in comparison to every other drive tested.  We didn’t believe this and subsequently repeated the test three times with the same results.


The strength of the  WD_Black SN850 Gen 4 NVMe SSD is a very welcome introduction to the SSD arena as it contains a WD/SanDisk proprietary 8-channel controller that nobody really expected to perform as it does.  It is the poker hand that nobody saw coming.  Performance of the SN850 was found to be very strong throughout our test regimen, given exception to the issue of heat with ATTO itself.

The high temperatures that have become commonplace in PCIe 4 have to be a paramount concern to manufacturers.  We are not going to see Gen 4 full power SSDs in laptops or ultrabooks any time soon if the temperature isn’t brought down to present Gen 3 levels.


Totally unexpected was our true data testing where the transfer of very small OS files was done at half the time of any other SSD we had ever tested.  Thinking this was a fluke, we repeated this test over and over again with the same results.  We have passed over something else in hopes that the reader might simply pick this up over time… Our synthetic benchmarks collectively are the best we have seen yet from a released product and surpass the Samsung 980 Pro by a stretch.  CDM. AS SSD. Anvil. AJA. TxBench….as well as our True Data Transfer Tests.

The WD Black SN580 Gen 4 NVMe SSD is a strong performer with a 5-year warranty, and pricing as we might expect to see from such a release.  Included with this is the ability to download a free copy of Acronis true Image but, even better yet, Western Digital’s SSD Dashboard is one of the best we have seen yet with a very professional appearance, simple navigation with a bevy of features to maintain the performance of your SSD. The only suggestion we might put forward would be to drop pricing just a bit to make it competitive with the Samsung 980 Pro.

Check WD_Black SN850 Pricing at Amazon.



WD_Black SN850 Gen 4 NVMe SSD Ratings

Product Build
5-Year Warranty
Pricing And Availability

Pure Speed!

The WD_Black SN850 is a proven performer with a 5-year warranty, mass availability, as well as a decent price.

Check Amazon
User Rating: 4.26 ( 1 votes)


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    The Real World File Transfer Comparison is amazing! I suspect that with some firmware tweaking they’ll speed up the music and photo transfer as well.
    A quote from your review:

    “Not only are the throughput and IOPS high sequentials looking very good, but also, low 4k random read and write throughput is solid.”

    This reminds me of one of the many reasons I bought a 512GB Crucial MX100, based on your review on June 12, 2014:


    “While such high IOPS are nice to see, most consumers should be looking at the 4K performance of the drive. High queue depth speed results over queue depths 3-5 usually don’t matter much for typical consumer desktop usage.”

    Right after you released this review, I built a new PC using the MX100 with all new components. I’m still using the MX100 (with all of the same components), but I plan on upgrading after we see finished-product E18 reviews, and AMD Zen3 CPUs become more plentiful.

    Since I’m one of the “typical consumer desktop” users, I still pay very close attention to the random 4K Q1T1. While I don’t know if this drive reviewed here is the fastest at random 4K, it still looks very good to me.
    In the meantime, I’m still stuck with a sequential read/write around 500 MB/s and random 4K read/write of 33.8 and 136.1 MB/s. My PC might be as slow as molasses compared to all of the new hardware, but it still works okay for being all 2014 hardware. I think I heard somewhere that patience is a virtue.
    Seriously though, it’s time to build a new PC with all new components, except for the case (Antec Solo).
    BTW, Crucial Storage Executive still reports that my MX100 is almost like new. It’s been a very dependable SSD.

    Thanks for another excellent review, Les.

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    @thessdreview staff: thanks for the review! When I checked the PCMark8 comparison chart I was a bit surprised that the Samsung 970 Pro 1TB is still ranked 2nd, while the 980 is tailing way behind. Any ideas why the difference between the two drives is that big?

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