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WD Black SN770 review: a fast drive with stiff competition

This Western Digital PCIe 4.0 M.2 SSD offers decent overall speeds for a reasonable price, but cheaper drives offer similar real-world performance.

The WD_Black SN770 SSD being placed into the motherboard slot

Our Verdict

The WD Black SN770 is fast and reasonably priced for a PCIe 4.0 M.2 SSD, but there’s stiff competition above and below it in this busy marketplace.

Reasons to buy
  • Excellent performance
  • Reasonable price
  • Doesn't throttle without heatsink
Reasons to avoid
  • Not much cheaper than SN850
  • Cheaper SSDs offer similar real-world performance
  • Average endurance rating

It’s easy to get confused over WD’s naming schemes for its SSDs, but in general, if it’s Black it’s going to be fast, if it’s Blue it’s going to be not quite so fast, and if it’s Red it’s going to have a decent endurance rating. The problem is that there are then different model names within those lineups. The WD Black SN770 we’re reviewing here isn’t the only Black series SSD to sit in WD’s arsenal, but it is one worth considering – especially if it’s on sale.

The big question, then, is how does the SN770 stack up against some of the best SSDs for gaming? To find out, we’ve put the drive to the test in our labs, looking at its overall performance and operating temperature versus the competition, including the manufacturer’s flagship WD Black SN850 drive.

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The WD Black SN770 specs list is:

Interface PCIe 4.0
Capacities 250GB, 500GB, 1TB, 2TB
Formatted capacity 931TB (1TB version)
Max claimed sequential read/write speed 5,150MB/s, 4,850MB/s (2TB)
Max claimed random read/write speed 740k/800k IOPS (2TB)
Controller WD in-house
Endurance rating 600TBW (1TB)
Warranty Five years


It’s only when you get to the performance numbers that you see the difference between the SN860 and SN770. The SN850 tops out at a claimed 7,000MB/s read speed for all three capacities, while the SN770’s maximum claimed read speed hovers around 5,000MB/s unless you dip down to 250GB, where it drops to 4,000MB/sec.

Write speeds follow a similar pattern, with 5,000MB/s claim for the SN770 at 1TB and 2TB, which drops down to 4,000MB/s at 500GB and 2,000MB/s at 250GB. The SN850, meanwhile, manages an extra 1,000MB/s at 2TB and 1GB, at least in WD’s claims.

Under the hood is a WD in-house four-channel controller with triple-level cell (TLC) NAND flash memory, but no DRAM for caching. Instead, the SSD relies on system RAM and speedy BiCS5 112-layer TLC memory to ensure the real-world speeds are what you’d expect from a modern PCIe 4.0 SSD.

The WD Black Sn770 SSD in the NVMe slot

Like the Kingston Fury Renegade, there’s also no heatsink on the SN770, which can potentially lead PCIe 4.0 SSDs to thermal throttle. However, with no heatsink attached, the SN770 peaked at the same 71°C temperature as the Kingston drive, but only after a back-to-back run of CrystalDiskMark being used as a stress test, during which it managed to still hit 5,226MB/s read and 4,970MB/s write speeds, even beating WD’s claims. Donning our motherboard’s heatsink saw no improvement in speeds, though, unlike the Kingston drive.

Meanwhile, the SN770’s 4K random 32-queue-depth, four-thread read speed of 2,255MB/s was on par with that of the SN850, which managed 2,172MB/s – a difference that’s barely worth mentioning.

It was a similar situation for the SN770’s 4K write speed of 1,932MB/s, which was also more than a match for any other PCIe 4.0 SSD we’ve tested, including the Kingston Fury Renegade. In AS-SSD, though, the Kingston SSD added 1,000MB/s to the WD SN770’s sequential read speed.


The WD Black SN770 comes in several drive sizes: 250GB, 500GB, 1TB, and 2TB. We’re testing the 1TB drive here, which has an MSRP of $99.99 (£82.99). The 2TB drive has an RRP of $149.99 (£139.99).

There are regular savings on these SSDs at many stores, though, so keep your eyes peeled for a bargain.


Current pricing for the WD Black SN770 sees it offering decent value for a PCIe 4.0 M.2 SSD, thanks to its solid performance in both sequential and random tests. However, it’s up against a lot of competition in this crowded market, not least from WD’s own drives.

Even at $125 for a 1TB drive, though, you’d need some very good reasons to pick it over the WD Blue SN570, which costs $35 less and isn’t much slower in terms of real-world performance. Meanwhile, the WD Black SN850 is faster in sequential tests and costs only a little more money, making it a slightly better buy if you want the very best performance in all scenarios.

If you’re planning to upgrade your storage, make sure you also read our full guide on how to install an SSD, which takes you through every step of the process.