WD’s Black SN770 SSD delivers up to 5.15 GBps of throughput and 800,000 random IOPS over the PCIe 4.0 bus, all at an aggressive price point that redefines our expectations for a mainstream SSD in 2022. That makes it a top contender for our list of the best SSDs.
We recently took a closer look at WD’s Black SN750 SE, and while that was a surprising feat and sufficient for most cases, it was clear that the company had more in mind for the true successor to the Black SN750.
While the shift to a DRAM-less architecture was not what we expected, it appears that the new SN770 shares a similar design. Built with an efficient SSD controller and a single NAND package, the SN770 resembles its predecessors, but with speeds up to 5.15 GBps, it clearly takes a big step forward. So much so that it prompts us to rethink the definition of mainstream SSDs in 2022.
WD’s Black SN770 marks the beginning of an era where SSDs with speeds of 5GBps are mainstream options, while slower SSDs fall into the budget market. PCIe 3.0 SSDs with eight-channel controllers have had their day, but the WD Black SN770 beats them all – all while using an SSD controller that resembles a wolf in sheep’s clothing.
WD says the SN770 delivers up to 40% faster performance and up to 20% more power efficiency over its previous-generation SSD (1TB Black SN750 SE), thanks in part to the new DRAM-less four-channel SSD controller and TLC flash . While this is a seemingly disappointing combination of components, it gets the goods.
Specifications:
| Product | 250GB | 500 GB | 1TB | 2TB |
|---|---|---|---|---|
| Prices | $59.00 | $79.00 | $129.00 | $269.00 |
| Capacity (User / Raw) | 250GB / 256GB | 500GB / 512GB | 1000GB / 1024GB | 2000GB / 2048GB |
| form factor | M.2 2280 | M.2 2280 | M.2 2280 | M.2 2280 |
| Interface / Protocol | PCIe 4.0 x4 / NVMe 1.4 | PCIe 4.0 x4 / NVMe 1.4 | PCIe 4.0 x4 / NVMe 1.4 | PCIe 4.0 x4 / NVMe 1.4 |
| controller | WD NVMe Architecture | WD NVMe Architecture | WD NVMe Architecture | WD NVMe Architecture |
| drama | HMB | HMB | HMB | HMB |
| Memory | Kioxia BiCS5 112L TLC | Kioxia BiCS5 112L TLC | Kioxia BiCS5 112L TLC | Kioxia BiCS5 112L TLC |
| Sequential Read | 4,000MBps | 5,000MBps | 5,150 MBps | 5,150 MBps |
| Consecutive writing | 2,000MBps | 4,000MBps | 4,900MBps | 4,850 MBps |
| Random reading | 240,000 IOPS | 460,000 IOPS | 740,000 IOPS | 650,000 IOPS |
| Random writing | 470,000 IOPS | 800,000 IOPS | 800,000 IOPS | 800,000 IOPS |
| Security | N/A | N/A | N/A | N/A |
| Endurance (TBW) | 200TB | 300TB | 600TB | 1200 TB |
| part number | WDS250G3X0E | WDS500G3X0E | WDS100T3X0E | WDS200T3X0E |
| Guarantee | 5 years | 5 years | 5 years | 5 years |
The Black SN770 is capable of sequential speeds of up to 5.15/4.9 GBps read/write and up to 740,000/800,000 random read/write IOPS. The drive is available in 250GB, 500GB 1TB, and 2TB capacities with suggested retail prices ranging from $0.13-$0.24 per gigabyte. Pricing is somewhat aggressive, undercutting higher bandwidth PCIe 4.0 SSDs while still being competitive with the best PCIe 3.0 models.
WD backs the SN770 with a five-year warranty and medium endurance. It uses a multi-step LDPC ECC engine, RAID ECC, and comes with approximately 9.9% factory overprovisioning, all of which deliver up to 600TB of write time per 1TB of capacity within the five-year warranty (except for the 250GB SN770, which can accommodate up to 200 TB of writes).
Software & Accessories
The SN770 supports WD’s SSD dashboard. The software will automatically detect WD Black SSDs and enable the dark mode theme in the app. The software also allows you to monitor SSD capacity used, remaining endurance, and even performance in real time. Of course, you can use the software to update the firmware and also enable the game mode. Game Mode improves the performance of the SN770 by disabling the ability to switch to lower power modes, reducing latency and giving you a competitive advantage.
A closer look
The WD Black SN770 comes in an M.2 2280 single sided form factor and contains very few components on top of a nice black PCB. While we like the neat layout of the components, the label is a bit full of QR codes and text. Also, the label on the disc does not match the design on the box. Instead of a label covering all the components, our drive came with a smaller one between the controller and the NAND package, as shown.
Based on its size, the SSD controller appears to be a four-channel design, as seen on the SN570 and SN750 SE, but WD is tight-lipped. In terms of speed, it certainly surpasses the Phison PS5019-E19T powering the SN750 SE. In addition, we believe that the speed of the flash interface is also much faster.
WD says the SN770 supports advanced power management to stay cool and efficient during use. When used in a high temperature environment, it also comes with thermal throttling support that prioritizes data integrity over speed. In addition, it supports Trimming, SMART data reporting and secure erase via the Format NVM command. However, the WD Black SN770 does not support AES 256-bit hardware encryption.
Instead of onboard DRAM, the SN770 uses Host Memory Buffer (HMB) technology to access 64MB of RAM from the host system to store portions of the SSD mapping tables, speeding up performance.
The WD Black SN770 uses Kioxia’s BiCS5 112-Layer TLC, which is a huge upgrade over the last generation as it comes with a quad-plane architecture that enables twice the writing speed of BiCS4. However, while it increases performance, it also requires more peak power consumption under load due to the increase in word line and sense amplifier load.
There are sixteen 512Gb chips on our 1TB sample and they offer twice the write speed of Kioxia’s BiCS4 96-Layer TLC, which is especially important given the DRAM-less nature of this SSD. The flash features a CUA (circuitry under array) design that allows Kioxia to scale the flash more easily and skew peak power consumption over time. The company also introduced a 4KB page reading method that uses an all-bitline detection method that preloads every 4KB page to reduce power consumption by up to 40%.
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