Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse

WD's supremely powerful WD_Black SN850 SSD gets a flash upgrade to BiCS 5 with the SN850X, bringing a huge performance boost.

Published Aug 12, 2022 10:45 AM CDT   |   Updated Sun, Aug 21 2022 7:33 PM CDT
Manufacturer: Western Digital (WDS200T2X0E)
8 minute read time
TweakTown's Rating: 98%
TweakTown award

The Bottom Line

Absolutely stunning performance.

Pros

  • + Gaming
  • + Consumer Workloads
  • + Single Sided

Cons

  • - Current Amazon Pricing

Should you buy it?

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Introduction & Drive Details

Almost two years ago, Western Digital dropped what is still one of the best-performing SSDs ever made. Western Digital's WD_Black SN850 1TB stormed in ending the 1TB Samsung 980 Pro's brief one month reign as the best performing flash-based consumer SSD ever made, and doing so in spectacular fashion.

Its superior flash is the secret sauce behind the WD Black SN850's otherworldly performance. BiCS 4 96 Layer flash. BiCS 4 is so good it has only now just been overtaken by SK hynix 176 Layer as the top performing flash in circulation.

To those that doubt the veracity of our assertion that BiCS 4 performs better than Micron B47R or Samsung V-NAND, we can and have demonstrated this on multiple occasions. Whenever everything is equivalent except the flash (same controller, same DRAM), good ole 96 Layer BiCS 4 arrayed SSDs easily outperform 176 Layer B47R arrayed SSDs. A good example is the M10P vs. S70 Blade or FX900 Pro. B47R is more prolific but has never outperformed BiCS, period - end of story. Half the layers, older and still the better performer; that's just how superior BiCS architecture has proven to be. And we don't even need to get into how much better BiCS 4 is than V-NAND because even B47R arrayed SSDs easily outperform Samsung's V-NAND arrayed 980 Pro.

Again, BiCS 4 has been the performance leader for almost two years now, only just being overtaken by SK hynix's newly minted 176 Layer flash in the past month or so. Okay, so what about BiCS 5? Well, that's the question we've wanted to be answered since crowning the SK hynix Platinum P41 as the best-performing flash-based consumer SSD ever made.

BiCS 5 has already been demonstrated via Western Digital's remarkable WD Black SN770, that a single package DRAMless 4-channel BiCS 5 arrayed SSD can overall outperform every B47R arrayed enthusiast grade SSD we've ever tested and even the clip the WD Black SN850 by a couple of hundred points. So BiCS 5 is obviously very potent, but what we've needed to really put things into perspective is a BiCS 5 arrayed flagship enthusiast grade SSD, which is exactly what we have on our bench today.

Unlike BiCS 4, which came in mainly 256Gbit and 512Gbit die densities, BiCS 5 comes in 512Gbit and 1024Gbit die densities. Sure, this translates to higher-capacity SSDs. However, this can be a double-edged sword cutting both ways. On the one hand, 512Gbit flash inherently offers better density but is also inherently more latent (slower) than equivalent 256Gbit flash. This is why the 1TB WD Black SN850 arrayed with 256Gbit flash outperforms the 512Gbit arrayed 2TB model. The same goes for the 980 Pro. The point here is that die density affects latency or speed. So, is 512Gbit BiCS 5 faster than 256Gbit BiCS 4? Let's find out.

Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 35 | TweakTown.com

Western Digital specs its newest consumer flagship offering as capable of up to 7,300 MB/s sequential read throughput and up to 6,600 MB/s sequential write throughput at 2TB and 4TB capacity points. We have no problem meeting and exceeding factory up to throughput speeds on our AMD-based test bench. Intel-based systems will incur a roughly 200 MB/s penalty in read throughput but will deliver far better overall performance since sequential throughput has little to do with real-world performance.

In terms of throughput, at least, BiCS 5 512Gbit is indeed serving up more bandwidth than 256Gbit BiCS 4, especially when programming or writing, where we see a 1,300 MB/s improvement over the SN850 1TB. Impressive.

Drive Details

Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 01 | TweakTown.com

Across the board, these are among the highest "up to" random IOPS factory specs we've seen for a flash-based consumer SSD. Unlike sequential throughput, random throughput is indeed performance that matters, so this is a good sign.

Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 02 | TweakTown.com
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 03 | TweakTown.comWestern Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 04 | TweakTown.com
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 05 | TweakTown.comWestern Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 06 | TweakTown.com

The Western Digital WD Black SN850X 2TB is a preferred single-sided design featuring a two-package flash array composed of BiCS 5 112-layer flash behind an 8-channel SanDisk controller and 2GB LPDDR4 onboard DRAM. This is the ideal configuration for maximum compatibility and power efficiency while delivering full Gen4 throughput.

Jon's Test System Specifications

Buy at Amazon

WD_Black SN850X 2TB NVMe PCIe Gen4 x4 M.2 SSD

TodayYesterday7 days ago30 days ago
$229.99$229.99$259.99
* Prices last scanned on 9/23/2022 at 10:58 pm CDT - prices may not be accurate, click links above for the latest price. We may earn an affiliate commission.

Sony PlayStation 5 - M.2 Storage Expansion

PS5 Read Performance

With Sony's wildly popular PlayStation 5 console now enabled for M.2 NVMe SSDs to be used as fast storage expansion, we include results for PS5 compatible SSDs we test as a part of our reviews going forward. We are utilizing the newest PS5 hardware and software versions.

Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 07 | TweakTown.com
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 08 | TweakTown.com

For 5,500 MB/s plus capable SSDs that don't have an adequately sized PS5 compatible heat sink or other SSDs where the heat sink provided doesn't fit and can be removed, we both use and recommend Sabrents unparalleled PS5 heat sink available here.

Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 09 | TweakTown.com
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 10 | TweakTown.com

We only chart SSDs that can deliver a minimum of 5,500 MB/s read, which is Sony's original recommendation. We note that with the latest PS5 software update, even SSDs that only do 4,200 MB/s no longer trigger a low-performance warning; nevertheless, we are sticking by Sony's original recommendation of 5,500 MB/s minimum read requirement.

Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 11 | TweakTown.com

6,500 MB/s read is the upper echelon of what PCIe Gen4 SSDs can deliver on a PS5 storage expansion slot, so excellent result here, even though it's ever so slightly lower than the BiCS 4 arrayed SN850 and M10P.

Synthetic Benchmarks: CDM, Anvil, ATTO

CrystalDiskMark

Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 12 | TweakTown.com
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 13 | TweakTown.com
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 14 | TweakTown.com
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 15 | TweakTown.com

The SN850X 2TB, as expected, delivers more sequential throughput than its 1TB predecessor. However, looking at its Q1T1 random read performance, we find the 2TB SN850X trailing the 1TB SN850 by 1%.

Anvil's Storage Utilities

Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 16 | TweakTown.com
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 17 | TweakTown.com
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 18 | TweakTown.com
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 19 | TweakTown.com

Anvil's read score is without question the best synthetic indicator of real-world performance. This is why we still run it. Here the SN850X 2TB shows itself to be significantly faster overall than its 1TB predecessor, second only to the SK hynix 176 Layer arrayed Platinum P41. This is our first indication SK hynix 176L may indeed slightly outperform BiCS 5. Max random read throughput indicates the same.

ATTO

Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 20 | TweakTown.com
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 21 | TweakTown.com
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 22 | TweakTown.com

Sequential performance at QD4 comes in significantly better than its predecessor. We are getting nearly full throughput at 128K transfers which is exactly what we are looking for when we run this test. Do keep in mind that sequential speeds, contrary to popular belief, have little bearing on how an SSD performs real-world tasks as the vast majority of data is random.

Real-World Testing: Transfers, 3DMark SSD Gaming Test, PCM10 Storage

Transfer Rates

Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 23 | TweakTown.com
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 24 | TweakTown.com

Our 100GB data transfer test is not your ordinary 100GB of data. Ours is a crushing mix composed of more than 62K files. Overall, write performance as it applies to the consumer realm is the least important performance metric, simply because the consumer realm is write infrequently, read frequently. For example, how many times is a game installed vs. how many times it's played? As expected, the SN850X can do it faster than its predecessor.

Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 25 | TweakTown.com
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 26 | TweakTown.com

160 MB/s separates the SN850X from the Platinum P41, less than 100 MB/s from its predecessor. The majority of SSDs on this chart land somewhere between 4,200 MB/s and 4,400 MB/s, so we need to look at the following benchmarks for more accurate real-world read performance.

3DMark SSD Gaming Test

UL's newest 3DMark SSD Gaming Test is the most comprehensive SSD gaming test ever devised. We consider it superior to testing against games themselves because, as a trace, it is much more consistent than variations that will occur between runs on the actual game itself. This test is in fact the same as running the actual game, just without the inconsistencies inherent to application testing.

In short, we believe that this is the world's best way to test an SSDs gaming prowess and accurately compare it against competing SSDs. The 3DMark SSD Gaming Test measures and scores the following:

  • Loading Battlefield V from launch to the main menu.
  • Loading Call of Duty Black Ops 4 from launch to the main menu.
  • Loading Overwatch from launch to the main menu.
  • Recording a 1080p gameplay video at 60 FPS with OBS (Open Broadcaster Software) while playing Overwatch.
  • Installing The Outer Worlds from the Epic Games Launcher.
  • Saving game progress in The Outer Worlds.
  • Copying the Steam folder for Counter-Strike Global Offensive from an external SSD to the system drive.
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 27 | TweakTown.com
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 28 | TweakTown.com

Gaming is a performance metric that matters to the majority of DIY consumers, especially to the enthusiast crowd that TweakTown caters to. Western Digital is marketing its WD Black SN850X at gamers, and it's easy to see why based on this result. It delivers the goods far better than B47R arrayed SSDs, and significantly better than the BiCS 4 arrayed M10P.

Considering it and its predecessor both employ the very same SanDisk 8-channel controller with the only difference being 256Gbit BiCS 4 vs. 512Gbit BiCS 5, we find this result to be powerful evidence that 512Gbit BiCS 5 flash is indeed faster than 256Gbit BiCS 4, but slightly slower than 176L hynix.

PCM10 Storage Tests

PCMark 10 Storage Test is the most advanced and most accurate real-world consumer storage test ever made. There are four different tests you can choose from; we run two of them.

The Full System Drive Benchmark and the Quick System Drive Benchmark. The Full System Drive Benchmark writes 204 GB of data over the duration of the test. The Quick System Drive Benchmark writes 23 GB of data over the duration of the test. These tests directly correlate with mainstream user experience.

PCMark 10 Full System Drive Benchmark

Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 29 | TweakTown.com
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 30 | TweakTown.com

This particular test writes 204GB data and covers a broad range of common consumer tasks, including booting Windows 10, file transfers, Adobe and Office applications, and startup times for games including Battlefield V, COD Black Ops 4, and Overwatch. Unlike synthetic numbers, this is comprehensive real-world data which is why we use it to rank SSDs in terms of user experience.

Here again, we see what we believe is a clearly defined pecking order in terms of overall flash performance being 176 Layer Hynix, 112 Layer BiCS 5, 96 Layer BiCS 4, with 176 Layer B47R bringing up the rear.

PCMark 10 Quick System Drive Benchmark

Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 31 | TweakTown.com
Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 32 | TweakTown.com

The runaway leader here continues to be Plextor's 1TB M10P which is an IG5236 controlled SSD arrayed with BiCS 4 256Gbit flash. Its performance advantage here over the rest is a result of its controller architecture absolutely loving this workload. If we go apples to apples, WD Black SN850 1TB arrayed with 256Gbit BiCS 4 vs. the SN850X arrayed with 512Gbit BiCS 5, we again see BiCS 5 performing better despite its die capacity disadvantage. Again, more compelling real-world evidence that our flash performance pecking order is correct.

Final Thoughts

Having just attended Flash Memory Summit and been present for KIOXIA's (WD's BiCS manufacturing partner) keynote, we are reminded of a point that was stressed at the presentation. More layers do not automatically mean better performance. More layers equaling better performance is the same type of commonly accepted marketing jargon as sequential throughput being an indicator of performance.

We've known this to be true from the day we first tested 176 Layer B47R flash because 96 Layer BiCS 4-based SSDs still easily outperformed B47R SSDs in real-world simulations, even though B47R produces better synthetic eye-candy. Basically, fluff vs. substance. Very effective fluff, as even some that should know better, even by their own results, continue to parrot the more layers is faster myth.

Now, as to our inclination to rank 176 Layer SK hynix flash as slightly better performing than 112 Layer BiCS 5, we think that to be the case, but we could be wrong about that simply because the difference falls into the range of it could be the controller. This is backed up by the fact that we still rank the 256Gbit BiCS 4 arrayed M10P ahead of the SN850X 2TB. And we already established that BiCS 5 512Gbit is indeed faster than BiCS 4 256Gbit, so the difference is clearly controller related and can be fairly substantial, as evidenced by the chart below:

Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 33 | TweakTown.com

We rank SSDs in terms of overall user experience (performance where it matters most) as expressed by PCMark 10 storage and 3DMark gaming storage tests. We consider a user experience score of 11K or more to verify an SSD as a TweakTown Elite performer. We feel comfortable in saying that as it stands today, without factoring in DirectStorage as we understand it, Western Digital's WD_Black SN850X is overall the second-best performing SSD available in the America's (Plextor's M10P is only sold in Asia).

Western Digital WD_Black SN850X 2TB SSD Review - BiCS 5 Powerhouse 34 | TweakTown.com

Western Digital's newest member of its legendary "Black" series is an absolute dream for gamers or anyone that values real-world results over marketing fluff. BiCS 5 may or may not be the best-performing flash currently in circulation. We couldn't determine that concretely today as hoped. However, we determined that the Western Digital WD_Black SN850X 2TB is really as good as it gets, eminently TweakTown Elite, and worthy of our highest award.

Buy at Amazon

Performance

100%

Quality

100%

Features

100%

Value

90%

Overall

98%

The Bottom Line

Absolutely stunning performance.

TweakTown award
98%

WD_Black SN850X 2TB NVMe PCIe Gen4 x4 M.2 SSD

TodayYesterday7 days ago30 days ago
$229.99$229.99$259.99
* Prices last scanned on 9/23/2022 at 10:58 pm CDT - prices may not be accurate, click links above for the latest price. We may earn an affiliate commission.

Jon joined the TweakTown team in 2013 and has since reviewed 100s of new storage products. Jon became a computer enthusiast when Windows XP launched. He was into water cooling and benching ATI video cards with modded drivers. Jon has been building computers for others for more than 10 years. Jon became a storage enthusiast the day he first booted an Intel X25-M G1 80GB SSD. Look for Jon to bring consumer SSD reviews into the spotlight.

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