WD_BLACK SN850X 4TB
The WD_BLACK SN850X 4TB costs $665.95 right now, or $0.166/GB. The 2TB is cheaper per gigabyte at $0.156/GB. Stepping up to the 8TB costs $924.05 more. It is rated for 2,400 TBW, about 1.3 TB of writes a day for 5 years.
Prices update daily and may differ at the retailer. This page contains affiliate links.
Where to buy the WD_BLACK SN850X 4TB
Every in-stock offer we track, cheapest first, across the 4 versions of this drive we list.
- NeweggPart WDS400T2X0E-00BCA0$665.95
- AmazonPart WDS400T2X0E-00BCA0$699.95
- AmazonHeatsink edition · Part WDS400T2XHE-00BCA0$769.00
- NeweggHeatsink edition · Part WDS400T2XHE-00BCA0$769.99
Price history
Lowest in the last 30 days: $665.95. Lowest in 60 days: $665.95.
Show the data as a table
| Date | Lowest price |
|---|---|
| Sep 25, 2026 | $666 |
| Sep 24, 2026 | $666 |
| Sep 23, 2026 | $666 |
| Sep 22, 2026 | $666 |
| Sep 21, 2026 | $666 |
| Sep 20, 2026 | $666 |
| Sep 19, 2026 | $666 |
Lowest in-stock price each day at Newegg and B&H, across every version of this drive we list (including heatsink editions). Lowest point $665.95 on Sep 19; latest $665.95. Amazon prices appear in the offer list but are not charted.
Specifications
Speed (rated)
- Sequential read
- 7,300 MB/s
- Sequential write
- 6,600 MB/s
- Random read (4K)
- 1.2M IOPS
- Random write (4K)
- 1.1M IOPS
- Interface
- PCIe 4.0 x4
Endurance
- Rated writes
- 2,400 TBW
- Warranty
- 5 years
That is about 1.3 TB of writes a day for 5 years. A typical gaming PC writes a small fraction of that.
Drive
- Capacity
- 4TB
- Form factor
- M.2 2280
- NAND type
- TLC
- Cache
- DRAM cache
- DRAM size
- 4 GB
Identity
- Part number
- WDS400T2X0E-00BCA0
- Other versions
- WDS400T2XHE-00BCA0, SDSP81400TAN-000E0, SDSP81400TAH-000E0
Does it fit a PS5?
Yes. It meets Sony's requirements: PCIe Gen4 or faster on four lanes, M.2, and at least 5,500 MB/s. Sony recommends adding a thin heatsink, which the PS5 slot has room for. Every drive that fits.
Quality score
How we score →Scored for a gaming PC from what the maker publishes: read speed against the level games are built around, capacity (under 1TB loses points), cache type, endurance per terabyte and warranty. Speed above the floor adds almost nothing.
Value weighs the score against the price, compared with other 4TB NVMe SSDs: this drive costs $166.49/TB against a typical $163.98/TB. At a typical price, value equals the score. Cheaper raises it and dearer lowers it, but price counts for less than quality.
A factor we hold no value for scores zero rather than being skipped, so a drive we know little about never outranks a fully documented one. A low score with low confidence means undocumented, not bad. This is a specification index, not a benchmark, and it only compares NVMe SSDs with each other.
See every capacity of the WD_BLACK SN850X on one page, or compare it with every other drive on the NVMe SSDs table.
Affiliate disclosure: Some links on this page are affiliate links — MaxMyBuild may earn a commission at no extra cost to you if you buy through them. As an Amazon Associate, MaxMyBuild earns from qualifying purchases. For Amazon, current price and availability are shown on the Amazon product page; product prices and availability are accurate as of the date and time of purchase and are subject to change. Prices shown for other retailers are approximate and may differ at checkout. “Search” links are non-affiliate and provided for convenience only.