The WD Black SN770 NVMe SSD, Western Digital’s latest PCI Express 4.0 internal solid-state drive, offers strong performance at a modest price ($129.99 for the 1TB drive we tested, with models starting at $59.99 for 256GB). This DRAM-less M.2 SSD set a new high mark in our PCMark 10 Overall Storage benchmark and did well in tasks such as program loading and file copying. Although it falls just short of unseating our budget internal SSD champ, the ADATA XPG Atom 50, the WD Black SN770 is well worth consideration by cash-strapped gamers.
A Cheap Yet Capable M.2 Player
The SN770 is a PCIe 4×4 drive manufactured on an M.2 Type-2280 (80mm long) “gumstick” printed circuit board. It employs the NVMe 1.4 protocol over the PCIe 4.0 bus. The drive combines 112-layer TLC NAND flash with a homegrown WD controller. (Check out our glossary of SSD terms if some of this jargon is new to you.)
The controller eschews the DRAM cache used by some pricier drives, instead enlisting your PC’s main memory as a host memory buffer (HMB). This makes the SN770 the latest of several recent M.2 drives to employ DRAM-less architecture; others include the XPG Atom 50 and the WD Blue SN570. Although dropping DRAM helps reduce a drive’s cost, it can potentially hurt performance, but there was scant evidence of that when we benchmarked the SN770 using our testbed system.
The SN770 can fit in a Sony PlayStation 5, but WD does not claim compatibility with that gaming console. Its sequential read speed is below Sony’s recommended 5,500MBps, and the PS5 does not support HMB architecture. The XPG Atom 50 suffers the same limitations, but ADATA still touts it as PS5-compatible. (Any M.2 SSD used in a PS5 will be a secondary drive primarily used for game storage, so peak speed is not the primary consideration. But we still recommend looking for a drive that meets Sony’s spec and asserts compatibility.)
The power-efficient drive (according to WD, it consumes 20% less power than its predecessor, the WD Black SN750) lacks a heat sink or spreader, relying on WD’s thermal management technology and any thermal hardware on your PC’s motherboard. This should be fine for typical use, though we prefer the added security of at least an optional snap-on heat spreader, which might only marginally add to an SSD’s thickness.
Available in capacities ranging from 250GB to 2TB, the SN770 offers good value in a PCI Express 4.0 solid-state drive. Its price divides out to 13 cents per gigabyte for the 1TB drive we tested, which is just a penny per gig more than the 1TB XPG Atom 50, the only capacity currently available for that Editors’ Choice drive (although ADATA says a 2TB version is due later this year). The 2TB WD Black SN770 doesn’t offer any cost savings (on a per-gigabyte basis) over the 1TB model, also coming in at 13 cents per gig.
The durability ratings for the WD Black SN770, as measured in terabytes written (TBW), are typical for a TLC-based drive. The WD Black SN850, the Crucial P5 Plus, and the Samsung SSD 980 Pro match its rated 600TBW for the 1TB model and 1,200TBW for 2TB, while the Kingston KC3000 has slightly higher ratings of 800TBW for 1TB and 1,600TBW for 2TB. The XPG Atom 50 is rated at 650TBW for 1TB.
A few PCIe 4.0 drives offer much higher durability ratings—the Corsair Force Series MP600 and the Silicon Power US70 are rated at 1,800TBW for 1TB and 3,600TBW for 2TB. Conversely, QLC-based drives like the Mushkin Delta and the Sabrent Rocket Q4 are less durable, rated at just 200TBW for 1TB, 400TBW for 2TB, and 800TBW for 4TB.
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 drives cited here.) WD’s warranty covers the SN770 for five years or until you hit the rated TBW figure in data writes, whichever comes first.
The SN770’s sequential speed ratings of 5,150MBps read and 4,900MBps write put it in the midrange of PCI Express 4.0 internal SSDs. Drives with comparable rated speeds include the ADATA XPG Atom 50 (5,000MBps read / 4,500MBps write), the Corsair MP600 (4,950MBps read / 4,250MBps write), and the MSI Spatium M470 (5,000MBps read / 4,400MBps write).
For software, the company provides the WD Black Dashboard, with which we’re familiar from other products in the lineup such as the WD Black SN850. The Dashboard lets you check the drive status (space allocated, volumes, and temperature), run S.M.A.R.T. diagnostics, enable Gaming Mode—which disables power saving—and update the firmware. One feature the drive does not offer is 256-bit AES hardware-based encryption, which we’ve seen on comparable drives including the XPG Atom 50.
Testing the WD SN770: Great at Workaday Tasks
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 WD Black SN770 through our internal solid-state drive benchmarks including PCMark 10 Storage and Crystal DiskMark 6.0. Crystal DiskMark’s sequential speed tests provide a traditional measure of drive throughput, simulating best-case, straight-line transfers of large files.
The SN770 slightly exceeded both its 5,150MBps read and 4,900MBps write ratings in Crystal DiskMark testing. Its 4K read and write scores effectively tied the best scores of our comparison drives.
The SN770 had the highest score in the group in PCMark 10’s overall storage test, which measures a drive’s ability to perform everyday tasks like loading programs and transferring files. In individual trace tests, the SN770 generally did well, with its strong file-copy and ISO-copy test scores, one of the best Windows booting scores, and gaming and creative-app launch scores in the middle of the pack.
Bargain-Bin Overachiever
The WD Black SN770 NVMe SSD doesn’t have the searing throughput of some blue-chip PCI Express 4.0 drives, but it did live up to its rated speeds in our tests and comes in at a lower price than most. It generally did great in our benchmarks, setting the pace in the PCMark 10 overall test and outperforming many drives with faster rated speeds in the trace tests.
The SN770 is pretty well matched against the Editors’ Choice award-winning ADATA XPG Atom 50. Its PCMark 10 overall score was better, though the Atom beat it in loading Windows and launching Adobe programs and games. Both drives are budget-friendly, although the SN770 sells at a marginally higher price. The SN770 offers the admirable WD Dashboard drive management software, but lacks the desirable 256-bit AES encryption of the Atom 50. It also lacks any heat dissipation hardware, whether a heatsink or less expensive heat spreader. But while the Atom 50 remains our top pick among budget internal SSDs, the SN770 is a highly capable alternative that runs right on its heels. We’d be happy with either.
