Western Digital's flagship high-performance internal solid-state drive, the WD Black SN850 (starts at $129.99 for 500GB; $249.99 for 1TB with heatsink as tested), does not disappoint. It turned in our highest score ever in PCMark 10's overall performance benchmark, and also matched its raw speed ratings in Crystal DiskMark testing. The SN850 comes fitted with a heatsink slim enough that the drive meets Sony's PlayStation 5 compatibility requirements. The same is true of the ADATA XPG Gammix S70 Blade, which costs considerably less per gigabyte, so the Blade retains its Editors' Choice award. But the WD Black SN850 is well worth considering if you want an elite drive for gaming or content creation
The SN850 is a four-lane PCI Express 4.0 drive employing 96-layer TLC 3D NAND flash memory. It's manufactured on an M.2 Type-2280 (80mm long) "gumstick" printed circuit board. It uses the NVMe 1.4 protocol over the PCIe 4.0 bus, and features a homegrown WD G2 (a.k.a. SanDisk 20-82-10035-A1) controller. (Puzzled by the M.2 and PCIe jargon? Check out our guide to SSD terminology.)Our Experts Have Tested 32 Products in the SSDs Category in the Past YearSince 1982, PCMag has tested and rated thousands of products to help you make better buying decisions. (See how we test.)
The SN850 is available either with or without a heatsink; our test model came with one attached. WD recommends the model with heatsink for use with a desktop PC or the PS5. Desktop use is obvious—even an M.2 SSD with a honking, finned heatsink will fit in nearly all desktops, and the SN850's industrial-chic heatsink is a relatively low, sleek addition—but a PS5? Not having a PlayStation 5 on hand to verify the fit, we crunched the numbers. According to Sony, the console's M.2 slot allows for up to 11.25mm of total clearance, and with the WD drive plus heatsink being about 8.8mm high, it should fit with a couple of millimeters to spare.
For software, the company provides the WD Black Dashboard, which we've seen in other products in the lineup such as the WD Black D50 Game Dock NVMe SSD. The Dashboard lets you check the drive status (space allocated, volumes, and temperature), run S.M.A.R.T. diagnostics, update the firmware, and control the SN850's modest RGB lighting display.
The SN850's list price is near the high end compared with other high-performance PCI Express 4 drives equipped with heatsinks (as opposed to thin heat spreaders). The MSI Spatium M480 lists at 23 cents per gigabyte for 1TB and 22 cents for 2TB, while the ADATA Gammix S70 lists at 20 cents per gig in both 1TB and 2TB capacities. The abovementioned ADATA Gammix S70 Blade is the best bargain at 16 cents per gigabyte for both its 1TB and 2TB versions. The TeamGroup T-Force Cardea Zero Z44Q sells for just 13 cents per gig (2TB), but as a drive with QLC-based memory it has low durability ratings, and its speeds are midrange.(Photo: Molly Flores)
The durability ratings for the WD Black SN850, as measured in terabytes written (TBW), are about average for a TLC-based drive. The Crucial P5 Plus matches its 600TBW rating for its 1TB model and 1,200TBW for the 2TB drive. The 1TB Samsung SSD 980 Pro is also rated at 600TBW. The Kingston KC3000 has slightly higher ratings of 800TBW for the 1TB version and 1,600TBW for the 2TB.
A few PCIe 4.0 drives offer still higher durability ratings—the Corsair Force Series MP600 and Silicon Power US70 are rated at 1,800TBW for 1TB and 3,600TBW for 2TB. QLC-based drives like the Mushkin Delta and Sabrent Rocket Q4 are rated at just 200TBW for 1TB, 400TBW for 2TB, and 800TBW for 4TB.(Photo: Molly Flores)
The "terabytes written" spec is a manufacturer's estimate of how much data can be written to a drive before some cells begin to fail and get taken out of service. (TBW tends to scale 1:1 with capacity, as with the SN850.) WD's warranty covers the drive for five years or until you hit the rated TBW figure in data writes, whichever comes first.
We test PCI Express 4.0 internal SSDs using a desktop testbed with an MSI X570 motherboard and AMD Ryzen CPU, 16GB of Corsair Dominator DDR4 memory clocked to 3,600MHz, and a discrete graphics card.
We put the SN850 through our usual suite of internal solid-state drive benchmarks, comprising Crystal DiskMark 6.0, PCMark 10 Storage, and AS-SSD. Crystal DiskMark's sequential speed tests provide a traditional measure of drive throughput, simulating best-case, straight-line transfers of large files.
The SN850 slightly exceeded its Crystal DiskMark read and write speed ratings, becoming only the second drive to clear the 7,000MBps mark in our testing. Its rated write speed of 5,300MBps is relatively low for a high-performance drive, but the SN850 surpassed it. Its 4K read and write results were fine, with scores near the top. Only in AS-SSD copy testing did it falter, with average results in ISO speed but low scores in both program speed and game speed.
The WD drive simply crushed its PCMark 10 tests. It turned in a high score—in fact, our highest ever—in the overall test, closely followed by the Crucial P5 Plus and Kingston KC3000. It virtually tied for the high score in loading Windows 10 with the P5 Plus and the Samsung SSD 980 Pro. In PCMark's game-launching tests, the SN850 was the fastest in Battlefield 5 and basically tied for the win in Overwatch. It also did very well in the copying tests, with a high score in our ISO copy and second place in file copy. It was also above average in launching Adobe Photoshop and Premiere Pro.
WD has steadily improved its performance-oriented consumer internal SSDs in the past few years, and the WD Black SN850 is its best yet. The drive aced our PCMark 10 tests, which measure a drive's speed in commonplace activities like launching programs and copying files. Although its sequential write speed is rated below some elite gaming-oriented drives like the ADATA XPG Gammix S70 Blade, at least the SN850 matched its own speed ratings, which many drives fail to do, sometimes by wide margins.(Photo: Molly Flores)
The SN850 employs a relatively slender heatsink that enables it to fit in the M.2 slot of a PlayStation 5, as well as meeting Sony's other requirements for a PS5 SSD. As we noted, the ADATA S70 Blade is also PS5-compatible and costs considerably less. That said, the WD Black SN850 NVMe SSD is a very capable and appealing drive that's well worth your consideration whether you're a gamer, content creator, or indeed anyone who wants a top-notch PCIe 4 solid-state drive.
The WD Black SN850 NVMe SSD comes with a heatsink thin enough that the drive will fit a PlayStation 5, and proved to be a whiz at tasks such as launching programs and copying files.
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