Western Digital SSD PCIe 4.0 x4 NVMe

The SN850X 4TB hits 7,300 MB/s sequential reads and writes, putting it in the 89th percentile for speed and the 93rd percentile for capacity. Endurance is solid at 2,400 TBW with a 5-year warranty. The catch is price, affordability sits at the 9th percentile, so you're paying a serious premium for that 4TB capacity.

Sequential reads and writes both hit 7,300 MB/s, which is basically the ceiling for PCIe 4.0. That puts the SN850X in the 89th percentile for speed, so it's one of the best on the market right now. The 6,600 MB/s write figure listed in some retailer specs is a bit conservative compared to what WD claims, but either way, you're looking at top-tier throughput. Moving large files around feels instant.

Random performance is more of a mixed bag. It lands in the 62nd percentile, which is solid but not spectacular. For gaming and general use, you won't notice the difference. For heavy database work or sustained random I/O, there are drives that do better. The 2,400 TBW endurance rating is above average, so you can hammer this drive with writes for years before it starts to sweat.

Against the Samsung 9100 PRO, the SN850X holds its own on sequential speed but gives up ground on random performance and features. The Kingston FURY Renegade G5 and Micron T710 are both strong alternatives that often undercut WD on price while offering similar endurance. The Crucial T700 pushes into PCIe 5.0 territory with higher peak speeds, but you'll need a Gen5 motherboard to take advantage of it. The SanDisk Black SN850X is essentially the same drive under a different brand, so if you see it cheaper, grab it. For pure 4TB capacity at Gen4 speeds, the SN850X is hard to beat, but the competition is closer than WD would like.

At $1,037 USD for the 4TB model, you're paying roughly $259 per terabyte. That's a steep premium compared to smaller drives, and the affordability percentile of 9 makes it clear this is not a budget pick. The INR 99,000 and JPY 154,800 listings tell the same story in their respective markets. You're paying for the combination of capacity and speed, and that combo is rare. If you need 4TB in a single M.2 slot, the price per gigabyte is actually reasonable for what you get. If you can live with 2TB, you'll save a lot of money and still get most of the performance.

The SN850X 4TB hits 7,300 MB/s sequential reads and writes, which puts it in the top tier of PCIe 4.0 drives in our database. That's the headline, but the 4TB capacity is the real story here. It lands in the 93rd percentile for capacity, meaning almost nothing else in this category gives you this much room on a single stick. For a PS5 or a workstation that eats through storage, that's a big deal.

But you're paying for it. Affordability sits at the 9th percentile, which is a polite way of saying this thing is expensive. The 2,400 TBW endurance rating is solid and the 5-year warranty gives some peace of mind, but the feature set is thin beyond the heatsink option. If you need 4TB of fast NVMe storage and you're willing to pay the premium, this drive delivers. If you don't need the capacity, there are cheaper ways to get similar speed.

If you don't need 4TB in a single drive, skip this. The affordability percentile of 9 means you're paying a huge premium for capacity you might not use. A 2TB drive with similar sequential speeds will cost significantly less and still handle gaming, boot, and general use without breaking a sweat. Also skip it if you're on a PCIe 5.0 motherboard and want the absolute fastest storage available, drives like the Crucial T700 will outpace it. And if you're building a portable setup, the 19.7 out of 100 portable score tells you this isn't the drive for that job.

The SN850X 4TB is a straightforward recommendation if you need maximum capacity in a single M.2 slot and you're on a PCIe 4.0 platform. The 7,300 MB/s sequential speeds are top-tier, the 2,400 TBW endurance is reassuring, and the 5-year warranty means WD stands behind it. The price is the main obstacle. At the 9th percentile for affordability, this is a luxury purchase. If you're building a PS5 with a massive game library or a workstation that needs fast local storage, the SN850X earns its keep. If you're just looking for a fast boot drive, buy something smaller and save the cash.