The WD Black SN850X, which Western Digital announced back in May, has arrived on the retail shelves. The PCIe 4.0 SSD flaunts read speeds up to 7300 MBps and aims to fight for a spot among the best SSDs.
The SN850X comes in a standard M.2 2280 form factor. Therefore, the SSD will fit both PCs and Sony's PlayStation 5 console. Western Digital sells the drive with an optional heatsink with RGB lighting to maintain peak performance. PlayStation 5 owners don’t have to worry about the bulky heatsink, either. Western Digital assured us that the heatsink version fits inside the console just fine.
Western Digital doesn't specify the controller or the type of 3D NAND used in the SN850X's fabrication. However, we expect the speedy drive to use one of the company's in-house PCIe 4.0 SSD controllers. The WD Black SN850 uses the WD Black G2 controller so Western Digital may use the same controller in the X variant. Judging from the SN850X's endurance ratings, the PCIe 4.0 drive is, in all likelihood, rocking TLC (triple-level cell) NAND. Unfortunately, we can't pinpoint which one. For reference, the original WD Black SN850 launched last year was on fourth-generation BiCS 96-layer NAND. Since then, Western Digital and Kioxia (formerly Toshiba) have developed 112-layer and 162-layer NAND chips so that the SN850X could use one of the two.
You'll find Western Digital's SN850X in capacities of 1TB, 2TB, and 4TB, but only the 1TB and 2TB models are available with the heatsink. Regardless of the capacity, the SN850X offers sequential read speeds up to 7,300 MBps. The sequential write speeds, on the other hand, do vary a bit between the different capacities. Only the 2TB and 4TB can hit 6,600 MBps, whereas the 1TB drive maxes out at 6,300 MBps, which isn't too shabby.
WD Black SN850X Specifications
| Product Number | Capacity | Sequential Read (MBps) | Sequential Write (MBps) | Random Read (IOPS) | Random Write (IOPS) | Endurance (TBW) | Heatsink | Pricing |
|---|---|---|---|---|---|---|---|---|
| WDS400T2X0E | 4TB | 7,300 | 6,600 | 1,200,000 | 1,100,000 | 2,400 | No | $699.99 |
| WDS200T2XHE | 2TB | 7,300 | 6,600 | 1,200,000 | 1,100,000 | 1,200 | Yes | $309.99 |
| WDS200T2X0E | 2TB | 7,300 | 6,600 | 1,200,000 | 1,100,000 | 1,200 | No | $289.99 |
| WDS100T2XHE | 1TB | 7,300 | 6,300 | 800,000 | 1,100,000 | 600 | Yes | $179.99 |
| WDS100T2X0E | 1TB | 7,300 | 6,300 | 800,000 | 1,100,000 | 600 | No | $159.99 |
The SN850X 2TB and 4TB SSDs deliver random read and write performance up to 1,200,000 IOPS and 1,100,000 IOPS, respectively. The 1TB version checks in with 800,000 IOPS reads and 1,100,000 IOPS writes.
If we compare the SN850X to the previous SN850, we're looking at 4% higher sequential reads and 25% higher sequential writes. Random read and write speeds have gone up 20% and 53%, respectively.
While the SN850X receives a substantial performance uplift, it's unfortunate that the SSD isn't more durable than its predecessor. Western Digital rates the SN850X 1TB, 2TB, and 4TB for 600 TBW, 1,200 TBW and 2,400 TBW, respectively. It's the exact endurance of the SN850 1TB and SN850 2TB. For the SN850, Western Digital didn't offer a 4TB model. The SN850X benefits from the vendor's limited five-year warranty.
The SN850X arrives with a revamped Western Digital Dashboard featuring Game Mode 2.0. Unfortunately, the vendor didn't share any details on the feature, except that it reportedly boosts PC performance. From the little available information, Game Mode 2.0 leverages predictive loading to prepare game assets for faster loading and adaptive thermal management techniques to optimize the SN850X's performance. Western Digital, in a blog post, admitted that the improvement is marginal, but it does make a difference.
Western Digital sells the 1TB drive for $159.99, the 2TB drive for $289.99, and the 4TB drive for $699.99 on its online store. The 1TB and 2TB models with the optional heatsink carry a $20 premium. There is a little discrepancy with the pricing if you purchase the SN850X from another retailer — for example, the SN850X 4TB (via momomo_us) retails for $820.37 on Amazon.
