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


SSD testing at TSSDR differs slightly, depending on whether we are looking at consumer or enterprise storage media. For our WD_Black SN850 Gen 4 NVMe M.2 SSD testing today, our goal is to test in a system that has been optimized and will reach top speeds possible.

We are using our ASRock X570 Creator Test Bench which is AMD based and contains the AMD Ryzen 3700x Gen 4 CPU.  Our PC has been overclocked from 3600Mhz to 4300MHz and memory has been set at a XMP profile of 2667MHz,



The components of this Test Bench are detailed below.  All hardware is linked for purchase and product sales may be reached by a simple click on the individual item. As well, the title is linked back to the individual build article where performance testing can be validated. Tons of credit to this Cougar Blazer Gaming Case paired with Corsair fans and Corsair iCue RGB software which make this our most attractive case to date


PC CHASSIS: Cougar Blazer Open Frame Gaming Mid-Tower Case
MOTHERBOARD: ASRock X570 Creator PCIe 4.0
CPU: AMD Ryzen 3700x
CPU COOLER: Corsair Hydro H150i  Pro RGB 360mm Liquid Cooling
POWER SUPPLY: Corsair RM850x 80Plus
GRAPHICS: MSI Armor Mk 2 Radeon RX570 OC
MEMORY: Corsair Vengeance LPX DDR4 3600MHz
STORAGE: Intel Optane 905P 1.5TB SSD
KEYBOARD: Corsair K57 Wireless Gaming
MOUSE: Corsair Dark Core RGB SE Wireless BT Gaming
OS Microsoft Windows 10 Pro 64 Bitblank


The software in use for today’s analysis is typical of many of our reviews and consists of Crystal Disk Info, ATTO Disk Benchmark, Crystal Disk Mark, AS SSD, Anvil’s Storage Utilities, AJA, TxBench, PCMark 8, and we will be conducting true testing data transfer comparisons. Our selection of software allows each to build on the last and to provide validation to results already obtained.


Crystal Disk Info is a great tool for displaying the characteristics and health of storage devices. It displays everything from temperatures, the number of hours the device has been powered, and even to the extent of informing you of the firmware of the device.


Crystal Disk Info validates that our SSD is running in PCIe 4.0 x4 (four lane), and also that NVMe 1.4 protocol is in use with features to include SMART, TRIM and VWC.


ATTO Disk Benchmark is perhaps one of the oldest benchmarks going and is definitely the main staple for manufacturer performance specifications. ATTO uses RAW or compressible data and, for our benchmarks, we use a set length of 256mb and test both the read and write performance of various transfer sizes ranging from 512b to 65mb. Manufacturers prefer this method of testing as it deals with raw (compressible) data rather than random (includes incompressible data) which, although more realistic, results in lower performance results.


This ATTO result is a bit unusual and, right around the 16MB test pattern size, the SSD started to throttle.  A quick check of CDI showed its temperature to be 92°C.  This was the only benchmark that we experienced a heat rise anything near this, which included our true data testing.  We believe that this simply may be a compatibility glitch with ATTO itself.


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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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