The Western Digital WD Black SN850 Review: A Very Fast PCIe 4.0 SSD
by Billy Tallis on March 18, 2021 12:50 PM ESTConclusion
The Western Digital WD Black SN850 has clearly established itself as a premium consumer SSD. It trades the lead with the Samsung 980 PRO on many tests but beats Samsung more often than not, making the WD Black SN850 the fastest PCIe 4.0 SSD we have tested so far.
Western Digital was slow to get into the NVMe game and at times it has seemed like they weren't trying very hard to go after the high end. But they're definitely serious contenders now. The high-end consumer SSD market is no longer just Samsung and the runners-up.
Overall the SN850 does have a few performance quirks, but no serious weaknesses to worry about. The SN850 has a bigger and faster SLC cache than most of the competition and generally seems better-optimized for client workloads than the 980 PRO.
The SN850 also tends to have a bit better power efficiency than the 980 PRO, though the SN850 can definitely end up drawing a lot of power to deliver such high performance. Western Digital has sacrificed some of the efficiency from their previous-generation drives, so the heatsink option makes more sense than it did for the SN750. But the heatsink should be no means be viewed as mandatory. Only the most intense niche workloads will be able to keep the SN850 busy long enough for thermal throttling to become a serious limitation.
Samsung and Western Digital are also facing stiff competition from numerous brands that are using the Phison E18 SSD controller. We don't have full benchmark results from any of those yet, but preliminary results indicate that while there may be no clear winner for the absolute fastest consumer SSD, the Western Digital SN850 is holding on to most of its individual benchmark wins. Later this year we're expecting another wave of Phison E18 drives to arrive using 176L 3D TLC NAND, which may shift the balance.
Some enthusiasts have bemoaned the switch away from MLC NAND (2 bits per cell) for high-end drives. But the WD Black SN850 shows that high-end TLC (3 bits per cell) drives now match or surpass the performance of the Samsung 970 PRO on almost every single metric, even the corner cases where the TLC+SLC caching strategy traditionally runs into trouble. The only remaining test where that last high-end MLC drive still has a significant advantage is sustained sequential write speed after any SLC cache has been filled. For the very narrow range of workloads where that might matter more than the significantly higher peak performance modern consumer TLC drives offer, there are plenty of enterprise TLC drives that don't use SLC caching at all.
MLC is now dead, and there's no compelling reason to bring it back (except for niche applications).
| Premium NVMe SSD Price Comparison March 18, 2021 |
|||||||
| 500 GB | 1 TB | 2 TB | 4 TB | ||||
| WD Black SN850 (without heatsink) |
$119.99 (24¢/GB) | $199.74 (20¢/GB) | $379.99 (19¢/GB) | ||||
| ADATA XPG Gammix S70 | $199.99 (20¢/GB) | $399.99 (20¢/GB) | |||||
| Corsair MP600 PRO (Phison E18) |
$224.99 (22¢/GB) | $434.99 (22¢/GB) | |||||
| Sabrent Rocket 4 Plus (Phison E18) |
$199.99 (20¢/GB) | $399.98 (20¢/GB) | $799.99 (20¢/GB) | ||||
| Samsung 980 PRO | $119.99 (24¢/GB) | $196.74 (20¢/GB) | $379.99 (19¢/GB) | ||||
| Inland Performance (Phison E16) |
$94.99 (19¢/GB) |
$178.99 (18¢/GB) | $329.99 (16¢/GB) | ||||
| Sabrent Rocket 4.0 (Phison E16) |
$89.99 (18¢/GB) |
$149.98 (15¢/GB) | $299.98 (15¢/GB) | ||||
| PCIe 3.0: | |||||||
| SK hynix Gold P31 | $74.99 (15¢/GB) |
$134.99 (13¢/GB) | |||||
| WD Black SN750 | $62.99 (13¢/GB) |
$138.08 (14¢/GB) | $299.99 (15¢/GB) | ||||
| Samsung 970 EVO Plus | $79.99 (16¢/GB) |
$164.99 (16¢/GB) | $319.99 (16¢/GB) | ||||
The top-tier PCIe 4.0 SSDs are all priced very similarly right now, accurately reflecting that they all provide about the same real-world performance. Western Digital's current pricing for the WD Black SN850 is definitely competitive in this context. For a lot of consumers shopping in this segment, the decision may come down to heatsink options and aesthetics. The older, somewhat slower and less efficient generation of PCIe 4.0 SSDs based on the Phison E16 controller includes some much more affordable drives that are only a bit more expensive than the top PCIe 3.0 SSDs.
For most use cases a PCIe 4.0 SSD is still definitely overkill as it won't offer meaningfully better real-world performance than a good PCIe 3.0 SSD. PCIe 4.0 SSDs are still largely lacking their killer app, and saving something like $65 on a 1TB drive to drop down to PCIe 3.0 definitely has an impact on the rest of a system build's budget. But for consumers that are convinced they have good reason to upgrade to PCIe 4.0 storage, the WD Black SN850 is worthy choice. It offers the satisfaction and bragging rights of one of the fastest drives available, and will not be significantly outclassed until PCIe 5.0 arrives.
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Billy Tallis - Friday, March 26, 2021 - link
A UPS vs power loss protection capacitors defend against slightly different sets of failure conditions, with a lot of overlap. A UPS will help save more data when the utility power goes out, but PLP caps will save data that a UPS couldn't if your PSU blows up or some other component failure inside the PC causes it to crash hard.wr3zzz - Friday, March 19, 2021 - link
Is there a benchmark that shows "real-world' performance are not worth the premium between PCIe 3.0 and PCIe 4.0? Like how it translates in terms of time saved. CPU benchmark for web page loading is a good example. The benchmark numbers might be 2x or 10x but it doesn't mean anything if it means 1 second vs. 0.1 second. On the other hand, the difference from HDD to SSD is from going minutes to seconds.The delta between 4.0 and 3.0 is so wide now. It doesn't do us any good by showing benchmark numbers that are 2x across the board between SN850 and SN750 but then recommend the value proposition just isn't there for PCIe 4.0 in the real world.
oRAirwolf - Friday, March 19, 2021 - link
I do agree that it would be nice if Anandtech would add some real world benchmarks to show use scenarios for the most common tasks like loading Windows, various video game load times, common program launching, etc. I have a very high-end rig but I still boot off of 3 x Samsung 850 evos in RAID 0 because as far as I can tell, there is no significant benefit to switching to an mvne drive for my use case of working from my desktop providing high level tech support and gaming.Oxford Guy - Sunday, March 21, 2021 - link
You should be able to compare the 'light' workload of 3.0 drives to the 'light' workload of 4.0 drives using their Bench comparison page.I'd pay particular attention to latency results. High latency can make things feel slow.
'The benchmark numbers might be 2x or 10x but it doesn't mean anything if it means 1 second vs. 0.1 second.'
Not true. .1 second latency (time to wake to do something) is a lot snappier than 1 second latency.
Morawka - Friday, March 19, 2021 - link
Excellent review. See if you guys can a Sabrent Rocket 4 Plus sample and do a review on it! It's supposedly a little faster that the WD 850 in synthetics, but perhaps a little slower in real-world usage. It will be a close match up, that's for sure.Billy Tallis - Friday, March 19, 2021 - link
I don't have a Rocket 4 Plus, but I have Micro Center's equivalent: Inland Performance Plus. It's currently running The Destroyer, and has already completed the synthetic tests. https://www.anandtech.com/bench/product/2732?vs=27...Oxford Guy - Sunday, March 21, 2021 - link
Glad to hear there is a firmware update. I wasn't sure that Inland drives would be eligible for them.Spunjji - Friday, March 19, 2021 - link
"MLC is now dead, and there's no compelling reason to bring it back"Oooof, that's gonna chafe the NAND conspiracy-theorists who frequent these hallowed comments 😅
Oxford Guy - Sunday, March 21, 2021 - link
3D fabrication made TLC viable. It has not remedied the deficiencies of QLC and now Intel is reportedly planning to push PLC onto consumers.There is nothing theoretical about:
• The fact that QLC only offers 30% more density, despite having a lot more voltage states than a 30% increase (diminished returns)
• QLC drives have not been priced low enough to make them worthwhile
• PLC is going to be worse
• Economy of scale is actively working against consumer value, by inflating the price of TLC
Failure of trolling noted.
FunBunny2 - Sunday, March 21, 2021 - link
"There is nothing theoretical about:"the fact that, what, no more than a handful make NAND. if they choose, whether through collusion or simultaneous profit-seeking, to sell only QLC and PLC what are you going to do about it? invoke the Defense Production Act to force SLC production at reduced prices? unfettered capitalism never favours the consumer.