WD Black SN850 1TB SSD Review – Enviable Speed

It’s hard to imagine a fast PC without an SSD in 2022. These devices can significantly speed up the loading of the OS and various programs and applications, even in systems with relatively weak processors and a small amount of RAM. When it comes to gaming, even next-gen consoles are already equipped with SSDs instead of HDDs, and PC gamers have begun to take full advantage of these drives even earlier. Cybersport.ru will tell you about one of these devices – WD Black SN850 – and also check how its declared characteristics correspond to reality.



  • Model: Western Digital Black SN850.
  • Capacity: 1 TB.
  • Form Factor: M.2 2280.
  • Interface: PCI Express 4.0 x4.
  • Controller: WD_Black G2.
  • Memory type: 3D TLC.
  • Sequential Read / Write Speeds: up to 7 / 5.1 GB / s.
  • Reading random blocks of 4KB (QD32): 1000K IOPS.
  • Writing random blocks 4KB (QD32): 710K IOPS.
  • Recording resource: 1 200 TB.
  • MTBF: 2 million hours.
  • Working temperature: from 0 ° C to 70 ° C.
  • Dimensions: 80 x 22 x 2.38 mm.

The WD Black SN850 is one of the fastest consumer SSDs on the market, with up to 7GB / s read and 5.1GB / s write speeds. The device is made in the M.2 form factor of 2280 standard size and is connected to the computer via the PCI Express x4 interface. The appearance of the SN850 is not much different from other similar devices, but it still has its own characteristics: the printed circuit board in this case is one-sided, that is, all modules are located on the same plane.

SSD WD Black SN850

The memory array itself includes two microcircuits, which are 96-layer 512-gigabit 3D TLC chips manufactured by KIOXIA. A 2 MB LPDDR4 buffer from Micron is responsible for data exchange. All this is controlled by an ARM Cortex-R processor.

Owners of WD Black SN850 SSDs can install the proprietary Western Digital SSD Dashboard software. It has a huge number of tools for monitoring device parameters: volume, including occupied / free, temperature, firmware version (here it can be updated if necessary). The functionality also allows you to clone a disk in case you need to transfer all your data, including the operating system, to another drive.


WD Black SN850 demonstrates the maximum speed values ​​when using the PCI Express x4 4.0 interface. However, its mass adoption began only three or four years ago, and many of us still have computers with PCIe 3.0. We tested with two benchmarks on two benches with different interfaces – AS SSD Benchmark and CrystalDiskMark.

Testing the WD Black SN850 with AS SSD Benchmark

As expected, when connected via PCIe 3.0, the speed decreased almost twice, but it still matches the results of the best SSD-drives created for this interface. The WD Black SN850 is fully disclosed only on PCIe 4.0, and the speeds declared by the manufacturer are very close to those obtained using the benchmarks.

During testing, one feature of this SSD-drive was discovered – very high heating. On PCIe 3.0, the temperature never exceeded 58 degrees, that is, you can load the WD Black SN850 on such hardware endlessly – there is no way to overheat it. But on PCIe 4.0 we were able to get even 92 degrees, which is beyond the operating temperature specified in the specifications. When this happens, the read and write speed drops to about 2.5-3 GB / s, that is, to the values ​​we got on PCIe 3.0. This means that for stable operation at high speeds and long-term loads, it is necessary to use cooling. Some PCIe 4.0 motherboards have a built-in heatsink for the SSD, but in our case there was no such option.


The WD Black SN850 has proven in practice its declared characteristics, which correspond to the top consumer models. This drive is designed for the new PCI Express 4.0 interface, and only in such conditions it is able to fully reveal its potential. During normal use, most likely, it will not overheat, however, under prolonged loads, the temperature goes beyond the operating values, which temporarily reduces the write and read speed. If we use WD Black SN850 on computers with PCI Express 3.0, then we will get a fast enough SSD that will not overheat under any load. In general, regardless of the purpose of your PC or laptop, the WD Black SN850 will satisfy all your needs, while its only drawback will never appear in 90% of tasks that are put before a work or gaming computer.