Now Sold As the SanDisk Optimus GX PRO 850X#

The WD_BLACK SN850X's product listing now says the product "has been replaced by our latest generation" and points to the SanDisk Optimus GX PRO 850X. SanDisk sells the GX PRO 850X with or without a heatsink and rates it up to 7,300 MB/s read and 6,600 MB/s write on the 2TB and 4TB models, with a 5-year limited warranty. SanDisk also states that the heatsink version is compatible with PS5 and PS5 Pro consoles.

2TB with heatsink: View on Amazon

Everything below this section — the figures and the verdict — describes the WD_BLACK SN850X, not its successor.

At a Glance#

Product : WD_BLACK SN850X (with Heatsink) NVMe SSD

Brand : WD_BLACK (Western Digital)

Best For : PS5 owners who want an M.2 expansion drive with the heatsink already attached

Form Factor : M.2 2280, PCIe Gen4 x4, with a pre-installed heatsink

Key Highlights:

Sequential reads up to 7,300 MB/s on the 1TB to 4TB models, above the 5,500 MB/s or faster that Sony recommends
Its maker lists the PlayStation 5 as compatible with the heatsink model only
Its maker says the heatsink helps maintain peak performance through intense gaming sessions
Heatsink model in 1TB, 2TB, 4TB and 8TB
5-year limited warranty, with endurance from 600 TBW (1TB) to 4,800 TBW (8TB)

Who Should Buy This#

The WD_BLACK SN850X with heatsink is for PS5 owners who want more room for games without deleting one to install another.

Perfect for:

The out-of-space PS5 owner who already juggles installs and uninstalls every week
The collector who wants an entire rotation of large games installed and ready to launch
The new-PS5 owner adding a second drive before the internal SSD fills up
The console-only buyer who wants a drive that already has the heatsink attached

Exceeds Sony's Recommended Read Speed#

Sony recommends a sequential read speed of 5,500MB/s or faster for an M.2 SSD in the PS5. The SN850X's maker rates the 1TB, 2TB and 4TB heatsink models for sequential reads up to 7,300 MB/s, and the 8TB model for up to 7,200 MB/s.

Sony also notes that not all games necessarily play with the same performance as on the console's internal SSD, even when an M.2 SSD reads faster than 5,500MB/s.

Pre-Installed Heatsink for the PS5 Bay#

Sony says an M.2 SSD in the PS5 requires effective heat dissipation with a cooling structure, such as a heatsink and a heat transfer sheet, and that some M.2 SSDs come with cooling structures built in. The heatsink version of the SN850X is one of them: its maker lists the PlayStation 5 as compatible with the heatsink model only.

Its maker describes the heatsink version as helping to maintain peak performance through your most intense gaming sessions.

Capacities Mapped to Your Game Library#

The SN850X with heatsink comes in 1TB, 2TB, 4TB and 8TB, all within the 250 GB to 8 TB range Sony supports for an M.2 SSD.

1TB : A starter expansion for players who keep a focused library and rotate a handful of games at a time.

2TB : Room for a deeper library of large titles. To buy a 2TB model with a heatsink, see the SanDisk Optimus GX PRO 850X section at the top of this page.

4TB : For the serial installer who wants a large catalog of big games installed at once.

8TB : The largest heatsink model, for the biggest libraries.

Warranty and Endurance#

The SN850X carries a 5-year limited warranty. Endurance scales with capacity: its maker rates the 1TB heatsink model for 600 TBW, the 2TB for 1,200 TBW, the 4TB for 2,400 TBW and the 8TB for 4,800 TBW. TBW, or terabytes written, is the total volume of data the drive is rated to handle over its life.

Technical Specifications#

Interface : PCIe Gen4 x4, NVMe

Form Factor : M.2 2280, with pre-installed heatsink

Sequential Read : Up to 7,300 MB/s (1TB to 4TB); up to 7,200 MB/s (8TB)

Sequential Write : Up to 6,300 MB/s (1TB); up to 6,600 MB/s (2TB, 4TB and 8TB)

Random Read/Write : Up to 1,200K / 1,100K IOPS (2TB)

Capacities : 1TB, 2TB, 4TB, 8TB

Endurance (TBW) : 600 TBW (1TB) / 1,200 TBW (2TB) / 2,400 TBW (4TB) / 4,800 TBW (8TB)

PS5 Compatibility : Listed by its maker for the heatsink model only

Warranty : 5-year limited warranty

Pros & Cons#

Pros:

Reads up to 7,300 MB/s (1TB to 4TB), above the 5,500 MB/s Sony recommends
Heatsink comes pre-installed, and its maker lists the PlayStation 5 as compatible with the heatsink model
Endurance ratings from 600 TBW (1TB) to 4,800 TBW (8TB)
5-year limited warranty
Four capacities, from 1TB to 8TB

Cons:

Its product listing says it has been replaced by the SanDisk Optimus GX PRO 850X
The WD_BLACK Dashboard, which turns on Game Mode 2.0, is Windows-only and not usable from the PS5

Final Verdict#

The WD_BLACK SN850X with heatsink is rated to read faster than the 5,500 MB/s Sony recommends, and its maker lists the PlayStation 5 as compatible with the heatsink model. It carries a 5-year limited warranty and comes in 1TB to 8TB. Its product listing now says it has been replaced by the SanDisk Optimus GX PRO 850X. To buy, see the SanDisk Optimus GX PRO 850X section at the top of this page.

If you also build on PC and want a bare drive, see our roundup of the best NVMe SSD for a gaming PC. See also our WD_BLACK SN850X review.