WD Black SN850X Review: A Solid NVMe SSD

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.

In reality, it’s just a more expensive alternative — the “X” doesn’t hold much, whether or not it’s supposed to mean “extreme,” “extra”, or “the X factor,” as Western Digital puts it.

To be fair, the new drive is still an excellent SSD. It’s just not outright better than the predecessor. The notion that it is seems forced and just simply untrue. That’s partly because, in the world of NVMe PCIe 4.0 SSDs, the difference between all drives is somewhat negligible, to begin with.

In real-world usage, you’ll likely experience zero difference in this drive vs SN850 matchup, other than the new 4TB capacity of the former. And in synthesized random access or copy testing, the two are also neck and neck for the most part.

Between these two, get whichever fits your budget. And no matter which you get, you’ll be happy with the experience.

WD BLACK SN850X: That mysterious “X factor”

Physically, putting 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, this drive 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 noticeable slower performance (for a lower cost.) The other two are very similar.

Both are available in the naked and heatsink versions. This drive with heatsinks is available only in 2TB and 1TB capacities. 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.

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

This drive has the same endurance level as its predecessor, 600TBW, for each terabyte. Considering it comes with a 5-year warranty, that 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.

And also, like the case of previous WD BLACK NVMes, this drive 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.

But 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.

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

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 tossup.

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, this drive 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 heatsink.

Official Specifications by Capacity (2025 Datasheet)

Numbers below are the manufacturer ratings from the official SanDisk datasheet (August 2025), not estimates. Sequential speeds are up to values; endurance follows the JEDEC client workload.

Takeaway: the 2TB model is the sweet spot — full write speed and double the endurance of 1TB. PlayStation 5 owners must pick the heatsink model, and all capacities carry a 5-year warranty. Source: official SN850X datasheet (PDF).

Conclusion

The WD Black SN850X is an excellent NVMe SSD, though not as awesome as Western Digital would like you to believe.

Mostly, it’s a higher-capacity alternative to the previous SN850. In fact, the best thing about this drive 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. For a newer Gen5 challenger, see the AORUS Gen5 announcement; for a full gaming rig to host it, read our Alienware x17 R2 review and PCIe WiFi upgrade picks. But if you want the 4TB capacity, the WD BLAC SN850X is one of the current view available options.