Western Digital has unveiled a compact version of its WD_Black SN770 SSD, tailored mainly for handheld gaming consoles such as the Asus ROG Ally and Valve Steam Deck. The WD_Black SN770M delivers the performance typical of a midrange PCIe 4.0 SSD, with support for features like Microsoft's DirectStorage.

As implied by its name, the WD_Black SN770M is built on the same platform as its larger counterpart, the WD_Black SN770. It offers comparable performance metrics: sequential read speeds of up to 5150 MB/s, sequential write speeds of up to 4900 MB/s, and random read/write IOPS of up to 740K/800K. While the SN770M's figures might not rival the latest PCIe Gen5 drives, keep in mind that these are compact SSDs designed for portable, heat and power-constrained consoles.

Western Digital WD_BLACK SN770M SSD Specifications
Capacity 500 GB 1 TB 2 TB
Model WDS500G3X0G-00CHY0 WDS100T3X0G-00CHY0 WDS200T3X0G-00CHY0
Controller SanDisk
NAND Flash ?
Form-Factor, Interface Single-Sided M.2-2230, PCIe 4.0 x4, NVMe 1.4
Sequential Read 5000 MB/s 5150 MB/s
Sequential Write 4000 MB/s 4900 MB/s 4850 MB/s
Random Read IOPS 460K 740K 650K
Random Write IOPS 800K
Avg. Power Consumption ? W ? W ? W
Max. Power Consumption ? W (R)
? W (W)
? W (R)
? W (W)
? W (R)
? W (W)
SLC Caching Yes
TCG Opal Encryption No
MTTF 1.75M Hours
Warranty 5 years
Write Endurance 300 TBW
0.33 DWPD
600 TBW
0.33 DWPD
1200 TBW
0.33 DWPD
MSRP $74.99 $109.99 $219.99

Western Digital does not disclose what specific controller is or NAND is used in most of their drives these days. Notably, the company already offers an PCIe Gen 4 M.2-2230 drive for OEMs, the SN740, which lists the same performance specifications. So the SN770M may just be a retail redress of the SN740. Which, given how popular the SN740 has been as an aftermarket upgrade for the Steam Deck, it's more surprising that WD wasn't already selling a version of that drive in the retail market.

In terms of storage capacity, the WD_Black SN770M is available in 500 GB, 1 TB, and 2 TB variants, mirroring what its larger sibling provides. Given that both the Asus ROG Ally and Valve's Steam Deck ship with no more than 512 GB of storage, the 1 TB and 2 TB options present a substantial upgrade.

The 1TB model, priced at $109.99, is available exclusively through Western Digital's online store and Best Buy. In contrast, the 2TB version is sold only at Best Buy for $219.99. Currently, the 500 GB model is available for $74.99 from Western Digital's online store, as well as other e-tailers, retailers, and resellers. All these drives come with Western Digital's five-year limited warranty.

The M.2-2230 form factor was primarily developed for SSDs powering ultra-thin laptops, which typically don't demand top-tier performance. While there are indeed high-performance SSDs with the M.2-2230 form factor, most aren't designed for gaming systems. This makes it challenging for owners of portable consoles like the ROG Ally or Steam Deck to upgrade to a more advanced SSD. With the introduction of the WD_Black SN770M, Western Digital offers a retail solution tailored for gamers, blending solid performance with gaming-centric features, a combination rare in M.2-2230 drives.

Source: Western Digital

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  • Samus - Tuesday, September 12, 2023 - link

    I'd like to see real world results comparing these to the Hynix and Samsung competition, which are much cheaper (especially if you find an OEM one on eBay etc.)

    My experience with 2230-sized SSD's is they throttle almost immediately. The density of components and lack of a PCB let alone a heat spreader cause unpredictable burst performance. Immediately after installing a game update on my steamdeck, launching it took noticeably longer presumably because the drive was hot (I could feel it was hot through the chassis) and presumably because it was flushing the SLC out. I have an OEM Samsung PM991.

    At some point we need to realize its a losing battle with 2230 and PCIe 4.0 unless your application has headroom for a heatsink\cooling.
  • meacupla - Tuesday, September 12, 2023 - link

    I would add the Sabrent rocket to the 2TB 2230 mix.

    As for overheating, even OEM samsung SM951 2280 SSDs instantly overheat to 80C, or whatever their thermal throttling temperature is.
  • Samus - Tuesday, September 12, 2023 - link

    Yeah, that's kind of the joke about 2230. While modern controllers have gotten more efficient and NAND denser and process superior, performance has scaled along with it, so thermals aren't much better (though they are better...just look at the initial crop of NVMe PCIe 3.0 drives from Samsung that could cook an egg at idle.)

    Even the Hynix BC711 (P31 Gold OEM) in a 2230 form factor is pushing thermal limits and this controller (Cepheus) is considered one of the most efficient PCIe controllers, while surprisingly being one of the highest performance as well. But there is only so much you can do to manage throttling with zero airflow (in the case of the steamdeck around the M2 slot) and a tiny PCB dominated by a enormous package on package.
  • cyrusfox - Wednesday, September 13, 2023 - link

    I have been testing these in CFExpress type B adapters and by far WD is the best for performance/W(sn520/sn530/sn740/ & now sn770m). These run a lot longer and faster before thermal throttle compared to Micron and Kioxia I have tested against.

    I have not played with Samsung or Hynix 2230 ssds yet.
  • PeachNCream - Tuesday, September 19, 2023 - link

    If the design has room for cooling, it would arguably have room for a larger SSD. Though yeah, I guess length versus height can be a thing, but still there is a cost for the density.
  • dwillmore - Tuesday, September 12, 2023 - link

    I'm impressed that they pretty much jumped over 2242 and went right to 2230. There are a reasonable selection of 2242 NVME drives, but most are in the 256GB or lower range. This is a welcome development.

    Fortunately the designers of the M.2 standard foresaw this, so putting in a physically smaller drive into a normal slot is just a matter of moving a mounting stud. I'm sure there are a number of devices where that's not an option, but I would hazard to say that the majority of applications can handle it.
  • meacupla - Tuesday, September 12, 2023 - link

    and then many laptop makers decided to skimp on this feature, making m.2 slots only compatible with 1 size. That is, unless you use a more expensive aftermarket length adapter.
  • dwillmore - Wednesday, September 13, 2023 - link

    Or a little double sided tape.
  • meacupla - Thursday, September 14, 2023 - link

    I wouldn't trust double sided tape for a drive that will constantly hit 80C, with an unknown amount of wiggle room in the SSD compartment.
  • dwillmore - Thursday, September 14, 2023 - link


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