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WD Black SN850 M.2 NVMe SSD Review: Top-Tier Storage for Gamers and Pros (Updated)

With WD’s Black SN850 now in the lab, we will see if it really is ideal for those looking for fast, consistent storage.

WD Black SN850
Editor's Choice
(Image: © Tom's Hardware)

WD Black SN850 SSD

(Image credit: Tom's Hardware)

Performance Results for WD Black SN850 1TB

Rating: 4.5 (Editor's Choice) 

Verdict: WD’s Black SN850 is a high-performance PCIe 4.0 x4 M.2 NVMe SSD that was built from the ground up as the company’s fastest SSD for gamers and prosumers. Trading blows with Samsung’s best, it marks a dramatic improvement over its predecessor, ranking it as one of the best SSDs on the market.

FOR

+ Competitive performance
+ Large dynamic SLC cache
+ Black PCB
+ Software package
+ 5-year warranty

AGAINST

- Hot under heavy load
- High idle power consumption on desktop test bench
- AES 256-bit encryption not supported

Comparison Products for WD Black SN850 1TB

We threw the WD Black SN850 into the ring with its predecessor, the Black SN750, its little brother, the Blue SN550, as well as some of the best SSDs available. From Samsung, we included the 970 EVO Plus, 970 PRO, and the company’s newest flagship SSD, the 980 PRO. We also included the Team Group Cardea Ceramic C440, a PCIe Gen4 SSD powered by Phison’s E16 NVMe controller, and Intel’s ridiculously fast Optane SSD 905P. And, for some added Gen3 competition, we tossed SK hynix’s Gold P31and Crucial’s P5 into the mix.

Game Scene Loading - Final Fantasy XIV

Final Fantasy XIV Stormbringer is a free real-world game benchmark that easily and accurately compares game load times without the inaccuracy of using a stopwatch.

Final Fantasy XIV

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Intel’s Optane 905P is the fastest performing SSD in this game load benchmark, followed by the SK hynix and both the Samsung 970 and 980 PROs. WD’s Black SN850 takes fourth place, also delivering very responsive game load times and well ahead of the Phison E16-based Team Group. 

Transfer Rates – DiskBench

We use the DiskBench storage benchmarking tool to test file transfer performance with our own custom blocks of data. Our 50GB dataset includes 31,227 files of various types, like pictures, PDFs, and videos. Our 100GB dataset consists of 22,579 files, with 50GB of them being large movies. We copy the data sets to new folders and then follow-up with a read test of a newly-written 6.5GB zip file and 15GB movie file.

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DiskBench

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DiskBench

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DiskBench

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DiskBench

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When it comes to large file transfers, WD’s Black SN850 delivers top-notch results, outperforming Samsung’s best in three out of the four transfers. The Samsung 980 PRO copied the 50GB folder faster due to its slightly faster random performance. Still, the two essentially tied during the larger transfer, and WD’s Black SN850 displaced the Samsung 980 PRO as the fastest thing going when reading back our large test files.

Trace Testing – PCMark 10 Storage Tests

PCMark 10 is a trace-based benchmark that uses a wide-ranging set of real-world traces from popular applications and everyday tasks to measure the performance of storage devices. The quick benchmark is more relatable to those who use their PCs for leisure or basic office work, while the full benchmark relates more to power users.

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PCMark 10

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PCMark 10

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PCMark 10

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PCMark 10

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PCMark 10

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PCMark 10

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To say WD tweaked n’ tuned the Black SN850 is an understatement. WD’s Black went from just 'alright' with the SN750, to the SN850 now surpassing Samsung’s flagship SSD in both the Quick and Full Drive benchmarks. WD’s Black SN850 smashed the Samsung 980 PRO’s scores by 16% and 10%, respectively, marking a substantial improvement in the company’s SSD architecture.

Trace Testing – SPECworkstation 3

Like PCMark 10, SPECworkstation 3 is a trace-based benchmark, but it is designed to push the system harder by measuring workstation performance in professional applications.

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SPECworkstation 3

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SPECworkstation 3

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SPECworkstation 3

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Intel’s Optane SSD 905P is the current champ if you need the most responsive and durable SSD for your application, but WD’s Black delivers respectable results in comparison. WD’s Black SN850 was very responsive to SPECworkstation 3’s bombardment of diverse workloads but ultimately trails Samsung’s 980 PRO, scoring third place overall.

Synthetic Testing - ATTO / iometer

iometer is an advanced and highly configurable storage benchmarking tool while ATTO is a simple and free application that SSD vendors commonly use to assign sequential performance specifications to their products. Both of these tools give us insight into how the device handles different file sizes.

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ATTO

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ATTO

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ATTO

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ATTO

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ATTO

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ATTO

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ATTO

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ATTO

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ATTO

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ATTO

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We tested WD’s Black SN850 at a queue depth (QD) of 1 as it represents most day to day file access at various block sizes. WD’s Black SN850 delivers competitive sequential performance that even eclipses the test pool’s results at some file sizes, especially its write capability.  When bumping up the queue depth, peak sequential results clocked in at 7.1/5.2 GBps read/write with a 128KB block size, and write speed increased to just over 5.5 GBps when we increased the block size to 1MB.

In terms of random performance, WD’s Black delivers top-notch results with read latency clocking in at 0.048ms, roughly 21K IOPS at a QD of 1. Even scaling up to a QD of 128 the WD shows strong read and write performance, scoring first or second place in most metrics.

Sustained Write Performance and Cache Recovery

Official write specifications are only part of the performance picture. Most SSDs implement a write cache, which is a fast area of (usually) pseudo-SLC programmed flash that absorbs incoming data.  Sustained write speeds can suffer tremendously once the workload spills outside of the cache and into the "native" TLC or QLC flash. We use iometer to hammer the SSD with sequential writes for 15 minutes to measure both the size of the write cache and performance after the cache is saturated. We also monitor cache recovery via multiple idle rounds.

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Sustained Write Preformance

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Sustained Write Preformance

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Sustained Write Preformance

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Sustained Write Preformance

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Sustained Write Preformance

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WD’s nCache 4.0 enables massive dynamic SLC cache capacity while also maintaining consistent QoS by using a small and quick-to-recover static cache. From empty, our 1TB sample filled within 10 minutes, writing 300GB of data at a rate of 5.5 GBps before degrading to an average rate of 1.34 GBps. This propelled it well ahead of the competition up until roughly the five-minute mark, but it gave way to Samsung’s top drives along with Intel’s Optane 905P beyond that. 

Power Consumption and Temperature

We use the Quarch HD Programmable Power Module to gain a deeper understanding of power characteristics. Idle power consumption is an important aspect to consider, especially if you're looking for a laptop upgrade. Some SSDs can consume watts of power at idle while better-suited ones sip just milliwatts. Average workload power consumption and max consumption are two other aspects of power consumption, but performance-per-watt is more important. A drive might consume more power during any given workload, but accomplishing a task faster allows the drive to drop into an idle state more quickly, ultimately saving energy.

We also monitor the drive’s temperature via the S.M.A.R.T. data and an IR thermometer to see when (or if) thermal throttling kicks in and how it impacts performance. Bear in mind that results will vary based on the workload and ambient air temperature.

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Power

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Power

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Power

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Overall, Samsung’s 980 PRO is more efficient than the Black SN850 under load, but only by a small margin. WD’s Black SN850 consumes roughly 3.8W on average during the transfer test, with peak power consumption tipping the scales at roughly 6.8W. That's more than all other competitors. High idle power consumption may help the Black SN850 when it comes to responsiveness, but not efficiency.

This leads to WD’s Black SN850 running warm at idle with controller temperatures ranging from 47-50C, and it can get quite hot when pushed. After roughly 400GB of writes, our unit throttled once the controller hit 88 degrees Celsius, and its peak temperature measured was roughly 92 degrees Celsius in a 24 degrees Celsius room. For most consumer use cases, the 1TB WD Black won’t throttle to stay cool, but it may under heavy abuse without proper airflow or a heatsink.

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