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Deal.ai › WD BLACK
WD_BLACK
4TB WD_BLACK SN850X / SANDISK Optimus GX PRO 850X NVMe SSD (LIMIT 4)
WD_BLACK

4TB WD_BLACK SN850X / SANDISK Optimus GX PRO 850X NVMe SSD (LIMIT 4)

Best price now

$228.15at Newegg.comChecked 1 h ago

43% under what the other stores charge

Compared across 12 stores. Prices are checked against each store and labelled with when.

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Price facts

  • Lowest price today: $228.15 at Newegg.com (checked Nov 12, 2026).
  • Checked at 12 stores.

Our take on the 4TB WD_BLACK SN850X / SANDISK Optimus GX PRO 850X NVMe SSD (LIMIT 4)

The WD_BLACK SN850X is a PCIe 4.0 M.2 NVMe SSD built for gaming and heavy creative work, with sequential reads up to 7200MB/s. The 4TB model gives you room for a large game library plus video and project files on one drive. It is now sold under the SanDisk Optimus GX PRO 850X name, so the two names are the same drive. Reviewers rate it among the fastest Gen 4 drives, though it runs warm and needs a heatsink under sustained load.

Best forGamers with large librariesVideo editors and creatorsPS5 storage upgradesAnyone moving from SATA or Gen 3
Pros
  • Up to 7200MB/s sequential reads
  • 4TB capacity on a single M.2 drive
  • Game Mode 2.0 via WD_BLACK Dashboard
  • Strong sustained write performance
  • Same drive as the SanDisk Optimus GX PRO 850X
Cons
  • Runs hot under sustained load
  • Needs a heatsink for best results
  • Gen 4 speed, not Gen 5
  • Dashboard software is Windows only

4TB WD_BLACK SN850X / SANDISK Optimus GX PRO 850X NVMe SSD (LIMIT 4) prices at every store

  • Newegg.comNew

    In stockSold by roboshine

    $228.15Free shippingChecked 1 h ago
    Visit Newegg.com
  • Best BuyNew

    In stock

    $246.99Free shippingChecked 1 h ago
    Visit Best Buy
  • Office DepotNew

    In stock

    $498.99Free shippingChecked 1 h ago
    Visit Office Depot
  • eBayNew

    Availability unknownSold by department75

    $303.29Checked 1 h ago
    Visit eBay
  • BlueDogInkNew

    Availability unknown

    $356.14Checked 1 h ago
    Visit BlueDogInk
  • WalmartNew

    Availability unknown

    $396.99Checked 1 h ago
    Visit Walmart
  • OWCNew

    Availability unknown

    $399.99Checked 1 h ago
    Visit OWC
  • AmazonNew

    Availability unknown

    As an Amazon Associate, Deal.ai earns from qualifying purchases.

    $789.99Free shippingChecked 1 h ago
    Visit Amazon
  • Sonnet TechnologiesNew

    Availability unknown

    $1,799.99Checked 1 h ago
    Visit Sonnet Technologies
  • StaplesNew

    Availability unknown

    $1,936.56Checked 1 h ago
    Visit Staples
  • TargetNew

    Availability unknown

    $2,089.73Checked 1 h ago
    Visit Target
  • Central ComputersNew

    Out of stock

    $239.99+ $28.60 shippingChecked 1 h ago
    Visit Central Computers

Also available at

  • Sonnet Online Store - SONNETTECHCheck price at Sonnet Online Store - SONNETTECH

Store links may earn us a commission.

4TB WD_BLACK SN850X / SANDISK Optimus GX PRO 850X NVMe SSD (LIMIT 4) price history

Lowest price we've seen: $228.15 on Nov 12 at Newegg.com. Tracked across 12 stores since Nov 12.

What reviewers say

Reviewers consistently rank the SN850X among the fastest PCIe 4.0 drives, with near-advertised sequential speeds and strong real-world game loading. Owners praise the capacity and reliability of the 4TB model. The main complaints are heat and the need for a heatsink.

What people mention
  • SpeedPraisedReviewers say it hits close to its rated 7200MB/s reads and loads games fast.
  • HeatCriticisedOwners report high temperatures under sustained writes and recommend a heatsink.
  • CapacityPraisedThe 4TB model is valued for holding large game and media libraries on one drive.
  • SoftwareMixedThe WD_BLACK Dashboard is useful for Game Mode 2.0 but only runs on Windows.
  • ValueMixedBuyers see strong performance but note Gen 4 drives are now common and cheaper alternatives exist.

About the 4TB WD_BLACK SN850X / SANDISK Optimus GX PRO 850X NVMe SSD (LIMIT 4)

The 4TB WD_BLACK SN850X is an M.2 NVMe SSD that uses a PCIe 4.0 x4 interface. It has been renamed SANDISK Optimus GX PRO 850X. It is made for gaming, content creation, large file transfers and data-intensive applications.

Read speeds go up to 7,200 MB/s, with writes up to 6,600 MB/s. Performance may vary depending on the host device, usage conditions, remaining drive capacity and other factors. The drive supports Microsoft DirectStorage and works with Mac, Windows and Linux.

The downloadable Dashboard software (Windows only) monitors the drive's health and can automatically turn on Game Mode 2.0 when it detects a game.

Part number
WDS400T2X0E
Capacity
4 TB
Form factor
M.2 2280
Interface
PCIe 4.0 x4 NVMe
Sequential read
Up to 7,200 MB/s
Sequential write
Up to 6,600 MB/s
Endurance
4,800 TB total bytes written
Compatibility
Mac, Windows, Linux
Software
Dashboard (Windows only), Game Mode 2.0
Features
Predictive Loading, Overhead Balancing, Adaptive Thermal Management, DirectStorage support
Warranty
Limited 5-year warranty, support through SanDisk
In the box
4TB WD_BLACK SN850X M.2 NVMe PCIe Gen 4 SSD, retail package

Questions and answers

Is the SN850X the same as the SanDisk Optimus GX PRO 850X?
Yes. WD_BLACK renamed the SN850X to SanDisk Optimus GX PRO 850X. The part number WDS400T2X0E identifies the same 4TB drive.
Does it fit a PS5?
Yes, it is an M.2 2280 PCIe 4.0 drive, which fits the PS5 expansion slot. Sony requires a heatsink, so use a heatsink model or add one.
Do I need a heatsink?
For gaming and light work it runs fine with motherboard airflow. For sustained large transfers, a heatsink keeps temperatures down and avoids throttling.
Is it faster than a Gen 3 drive?
Yes, roughly double the sequential speed of typical Gen 3 drives. You will notice it most in large file transfers and game loading.
What is Game Mode 2.0?
It is a feature in the WD_BLACK Dashboard that tunes the drive for loading and streaming game data. The Dashboard runs on Windows only.
Is 4TB enough for a game library?
It holds dozens of large modern games plus room for video and project files. It suits users who want one drive for everything.
Where is the 4TB WD_BLACK SN850X / SANDISK Optimus GX PRO 850X NVMe SSD (LIMIT 4) cheapest?
At Newegg.com, for $228.15, 43% under what the other stores charge, as of our latest check.
Where can I buy the 4TB WD_BLACK SN850X / SANDISK Optimus GX PRO 850X NVMe SSD (LIMIT 4)?
12 stores we checked sell it, including Sonnet Technologies, Amazon, Newegg.com, Central Computers, Best Buy.

Stores we've priced the 4TB WD_BLACK SN850X / SANDISK Optimus GX PRO 850X NVMe SSD (LIMIT 4) at

  • Best Buy deals and prices
  • BlueDogInk deals and prices
  • Newegg deals and prices
  • Office Depot deals and prices
  • staples.com deals and prices
  • Target deals and prices
  • Walmart deals and prices
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