Western Digital WD_BLACK SN850X

The SN850X 4TB hits 7,300 MB/s read and 6,600 MB/s write, putting it among the best Gen4 drives we've tested. With a 4.9/5 rating from 514 reviews and social proof at the absolute top of our database, this is a drive people genuinely love. Catch it on sale and it's one of the best value high-capacity SSDs on the market.

Let's talk numbers, because this drive has them. The SN850X hits 7,300 MB/s sequential read and 6,600 MB/s write. That's not just fast, that's one of the best Gen4 drives on the market right now. The random performance is equally impressive, with 1,200K random read IOPS and 1,100K random write IOPS. For context, that's the kind of responsiveness that makes loading screens disappear and file transfers feel instant. The TLC NAND paired with DRAM cache and WD's own controller means sustained performance doesn't fall off a cliff when the drive gets full.

One real-world data point from a buyer: they benchmarked 7,133 MB/s read and 4,169 MB/s write in performance mode. That write number is lower than the spec sheet, but still blazing fast in practice. The Game Mode 2.0 feature with load prediction is a nice touch for gamers, though honestly this drive is fast enough that you might not notice the difference. It's also backward compatible with PCIe 3, so you can drop it in an older system and still get solid performance.

Stacked against the Samsung 9100 PRO, the SN850X holds its own on speed while often coming in cheaper, especially on sale. The Crucial T710 is another strong Gen4 competitor, but the WD drive's endurance rating of 2,400 TBW gives it an edge for heavy users. The Kingston Fury Renegade and Seagate FireCuda 530R are both solid drives, but neither matches the SN850X's combination of capacity, speed, and social proof. Where the SN850X really separates itself is in the 4TB capacity tier. Most competitors either don't offer 4TB or charge a premium for it. The SanDisk WD_BLACK SN8100 is essentially a sibling product, but the SN850X's Game Mode 2.0 and slightly better endurance numbers make it the better pick for gamers.

Here's where it gets interesting. The SN850X 4TB is priced anywhere from $600 to $800 in the US depending on where you shop. That's a $200 spread, which is significant. Best Buy has it listed with a price match guarantee, so if you find it cheaper elsewhere, they'll match it. In Canada, the spread is tighter at $900 to $1,000 CAD. The value story here is strong when you catch it on sale, which users consistently mention. At full price, it's harder to justify against some competitors. But when the price drops, this drive becomes one of the best performance-per-dollar options in the Gen4 space. Our data shows it scores 97.2 out of 100 for budget, which tells you the value proposition is real, especially at the lower end of that price range.

The WD Black SN850X 4TB is one of those drives that just gets it right. We're looking at 7,300 MB/s read and 6,600 MB/s write speeds, which puts it in the top tier of Gen4 drives we've tracked. The 4TB capacity is also a standout, landing in the 93rd percentile for storage space. That's a lot of games, a lot of video projects, a lot of whatever you throw at it. And with a 4.9 out of 5 rating across 514 reviews, people clearly aren't just buying it, they're loving it.

But here's the thing that jumps out at us: the social proof on this drive is off the charts, sitting at the absolute top of our database. That's not marketing fluff, that's real buyers consistently reporting the same thing. Fast, reliable, and worth the money. The endurance numbers back that up too, with 2,400 TBW and a 5-year warranty. You're not just buying speed, you're buying peace of mind.

If you're looking for a portable drive, this isn't it. The portable score of 25.8 out of 100 is one of the weakest areas in our database, so don't expect to slap this in an external enclosure and get great results. It's also not the best pick if you're on a strict budget and don't need 4TB. The $600 to $800 price range is a lot of money for storage, and a 2TB drive at half the price will serve most people just fine. And if you're building in a system with poor airflow and no M.2 heatsink, you'll want to factor in the cost of an aftermarket cooler, since this drive doesn't include one.

The WD Black SN850X 4TB is a top-tier Gen4 NVMe drive that earns its reputation. With 7,300 MB/s read speeds, a massive 4TB capacity, and endurance that'll outlast most builds, it's hard to find a real weakness here. The 4.9 out of 5 rating from 514 reviews isn't an accident. Users consistently report blazing speeds, easy installation, and excellent value, especially when it's on sale. The lack of a heatsink is a minor annoyance, and the firmware concerns are worth noting, but neither is a dealbreaker. If you need a high-capacity Gen4 drive and you can catch this at the lower end of its $600 to $800 price range, buy it without hesitation.