WD BLACK SN850X SSD Review (vs. SN850): A Spacious (and Pricier) Alternative

The WD Black SN850X, first announced in May 2022, is supposed to be the upgrade to the SN850, the flagship NVMe SSD in Western Digital's game-oriented WD BLACK family. It's a more expensive alternative—the "X" is supposed to mean "extreme," "extra", or "the X factor," as Western Digital puts it.

The new drive is still an excellent SSD. However, it's just not outright better than the predecessor, which supports the same technology. Generally, in the world of NVMe PCIe 4.0 SSDs, the difference between drives of the same grade is often negligible.

That said, in real-world usage, you'll likely experience little difference between the SN850X vs. SN850. But the former's larger capacities are sure to be a major advantage. So, if you want something 2TB or less, get whichever fits your budget. But if you need 4TB or more, give the SN850X a go. And in any case, you'll be happy with the purchase.

Update: On  July 16, 2024, WD unveiled the 8TB version of the drive, making it one of the highest capacity, if not the highest, among consumer-grade NVMe SSDs.

WD BLACK SN850X: That mysterious “X factor”

Physically, put the X at the end of the WD BLACK SN850, and you get the WD BLACK SN850X. The two share the same single-sided 2280 design of an NVMe SSD. It looks almost the same and comes in the same retail package.

On the inside, the SN850X is supposed to have faster hardware, but it's hard to know because WD generally doesn't disclose its SSDs' internal components. The company is also quite vague on what the drive has over its predecessor.

For example, the drive is supposed to have Game Mode 2.0 (as opposed to Game Mode on the older drives), and on this front, the storage maker says:

"The latest version of Game Mode serves up even more PC performance-boosting features like load prediction to ready game assets for fast in-game loading."

But just like the case of the SN850, Game Mode 2.0 proved to be a gimmick veneer. It didn't do anything tangible—more below.

Like the case of the Black SN770, the SN850 is part of the WD Black family: it's a storage device designed to deliver fast speed and not much else for gamers.

Hardware specifications: WD BLACK SN850X VS SN850 vs. SN770

Of these three, the SN770 is the lower tier with noticeably slower performance (for a lower cost.) The other two are very similar.

Both are available in the naked and heatsink versions. The new drive moves a capacity scale up a notch, starting with 1TB. It has lower MSRPs at launch but currently costs more on the street.

Name	WD Black SN850X	WD Black SN850	WD Black SN770
Capacity / Part Number	8TB / WDS800T2X0E 4TB / WDS400T2X0E 2TB / WDS200T2X0E 1TB / WDS100T2X0E	2TB / WDS200T1X0E-00AFY0 1TB / WDS100T1X0E-00AFY0 500GB / DS500G1X0E-00AFY0	2TB / WDS200T3X0E 1TB / WDS100T3X0E 500GB / WDS500G3X0E 250GB / WDS250G3X0E
Form Factors	M.2 2280  (80mm x 22mm x 2.38mm)
Weight (non-heatsink)	.27 oz (7.5g)		.2 oz (5.5g)
Interface	PCIe Gen 4 16GT/s, up to 4 Lanes PCIe Gen 3 and Gen 2 compatible	PCIe Gen 4 16GT/s, up to 4 Lanes PCIe Gen 3 and Gen 2 compatible	PCIe Gen 4 16GT/s, up to 4 Lanes PCIe Gen 3 and Gen 2 compatible
Endurance  (Terabytes Written)	8TB: 4800 TBW 4TB: 2400 TBW 2TB: 1200 TBW 1TB: 600 TBW	2TB: 1,200 TBW 1TB: 600 TBW 500GB: 300 TBW	2TB: 1,200 TBW 1TB: 600 TBW 500GB: 300 TBW 250GB: 200 TBW
Sequential Read (up to)	8TB: 7200MB/s 4TB: 7,300MB/s 2TB: 7,300MB/s 1TB: 7,300MB/s	2TB: 7,000MB/s 1TB: 7,000MB/s 500GB: 7,000MB/s	2TB: 5,150MB/s 1TB: 5,150MB/s 500GB: 5,000MB/s 250GB: 4,000MB/s
Sequential Write (up to)	8TB: 6600MB/s 4TB: 6,600MB/s 2TB: 6,600MB/s 1TB: 6,300MB/s	2TB: 5,100MB/s 1TB: 5,300MB/s 500GB: 4,100MB/s	2TB: 4,850MB/s 1TB: 4,900MB/s 500GB: 4,000MB/s 250GB: 2,000MB/s
Random Read: (up to)	8TB: 1200K IOPS 4TB: 1,200K IOPS 2TB: 1,200K IOPS 1TB: 800K IOPS	2TB: 1,000K IOPS 1TB: 1,000K IOPS 500GB: 810K IOPS	2TB: 650K IOPS 1TB: 740K IOPS 500GB: 460K IOPS 250GB: 240K IOPS
Random Write (up to)	8TB: 1200K IOPS 4TB: 1,100K IOPS 2TB: 1,100K IOPS 1TB: 1,100K IOPS	2TB: 710K IOPS 1TB: 720K IOPS 500GB: 680K IOPS	2TB: 800K IOPS 1TB: 800K IOPS 500GB: 800K IOPS 250GB: 470K IOPS
Warranty	5 Years
Release Date	August 2022	February 2021	February 2022
US MSRP (at launch, non-heatsink version)	1GB: $159.99 2GB: $289.99 4GB: $699.99 8TB: $849.99 (Amazon street price)	500GB: $169.99 1TB: $249.99 2TB: $449.99 (Amazon street price)	250GB: $49.99 500GB: $59.99 1TB: $109.99 2TB: $269.99 (Amazon street price)

WD Black SN850X: Frill-free feature set, standard endurance

The SN850X has the same endurance level as its predecessor, 600TBW, for each terabyte. It comes with a 5-year warranty, which translates into about .3DWPD (drive write per day).

Specifically, if you write a third of the 1TB version (some 333GB) to the drive daily and every day, that'd take five years to render it unusable.

Also, like the case of previous WD BLACK NVMes, the SN850X has no meaningful user-accessible feature, which is quite normal for a gaming SSD. No console has a way for users to manage the storage device's features; they all use the drive with its default manufacturer settings.

However, the drive does come with a helpful dashboard application for Windows users. The software allows for checking on its status, upgrading its firmware, and managing its so-called Game Mode 2.0, which is also only available to Windows users.

Some of the software's functions seemed buggy in my testing. For example, I needed to try the firmware update several times before it went through successfully.

You can only use the Dashboard to update the firmware when you use the SN850X as a secondary drive on a computer, which was my case. When using it as the boot drive, the software only helps you create a bootable USB thumb drive for the job.

On top of that, it didn't work well with the new Game Mode 2.0, either.

“Gaming Mode 2.0” is also gimmicky

Game Mode is supposedly a feature that boosts the SSD's performance when it works as the boot drive of a computer.

In my trial, the Game Mode was sometimes available on the Dashboard software's interface. Sometimes, it wasn't. It was just not there.

Most importantly, in my testing, the drive performance is practically the same with this feature turned on, off, or left in Auto mode. And that was the case with the SN850, too.

Nobody knows exactly what Game Mode does, but supposedly it puts the drive in full-power mode—the drive no longer goes to sleep when idle. If that's the case, you can only notice any improvement when you return to the computer after a break.

WD says with Game Mode 2.0, the Dashboard automatically detects gaming activities and "enables enhanced gaming features." That sounds like a bit of a stretch since there's not much an SSD can do to gaming activities when the game is already loaded.

Generally, if you want to conserve power, it's better to leave Game Mode off (default.)

WD Black SN850X: Detail photos

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WD Black SN850X: Excellent but not the best performance

The WD Black SN850X did well in my testing, proving one of the fastest NVMe SSDs. Compared with the SN850, though, it was a toss-up.

On the one hand, it was faster in copy speeds. On the other, it was consistently slower in random access synthetic tests.

In real-world usage, I purposely used both drives on the same computer with the same system image (for OS and software). I switch back and forth between the two, running the same tasks and playing the same game, and experience no difference.

And by the way, just like its predecessor, the SN850X delivered the same performance (within normal fluctuations) with Game Mode 2.0 turned on or off.

The WD BLACK SN850X ran slightly hot in my testing, though somewhat less hot than its predecessor. However, heat has been a common issue with PCIe 4.0 SSDs, which is why many are available with a heatsink.

Conclusion

The WD Black SN850X is an excellent NVMe SSD, though not as excellent as Western Digital would like you to believe. It's mostly a higher-capacity alternative to the previous SN850. In fact, the best thing about the SN850X is that it helps lower the street price of its predecessor.

Either drive will do you a solid in daily tasks and gaming alike. Pick whichever fits your budget. However, if you want 4TB or 8TB capacity, the WD BLAC SN850X is the only option.