WD SN740 2TB review: The M.2 2230 OEM SSD of choice | Tom's Hardware

The WD SN740 is a popular OEM M.2 2230 SSD that brings TLC and decent performance to the popular portable device form factor. The trade-offs are more power and heat, which are generally worthwhile.

Strong all-around performance

TLC at 2TB for single-sided M.2 2230

Runs a little hotter than desired

Not particularly power-efficient

OEM model

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The WD SN740 is one of the most popular M.2 2230 SSDs available for use in portable game systems like the Steam Deck, Steam Deck OLED, ASUS ROG Ally, Lenovo Legion Go, and more. Despite being an OEM drive, it achieved popularity because it offered the holy grail: 2TB of TLC NAND flash in a single-sided form factor. Most other TLC-based drives cap out at 1TB, while the use of QLC flash for 2TB requires compromises on performance. This made the SN740 and its rebrands top sellers, with the drive even being offered on Framework. WD would later capitalize on this popularity by releasing the retail WD Black SN770M.The WD SN740 remains popular, being widely available even though it's designed for system OEMs. It can often be found at a lower price than the SN770M, and otherwise the two drives are similar. The hardware on the two drives is the same, but there are some differences such as with the inferior write endurance, or TBW, specifications.The SN740 has the same faults as the SN770M, too: high power consumption and high temperatures under load. This can be a problematic combination for portable devices, though power-saving features mean the battery life at least wasn't compromised in our Steam Deck testing. One potential advantage of the SN740 is its optional support for hardware encryption, but that is a rather niche demand.For PCIe 3.0 devices like the Steam Deck we think QLC flash is quite fine, unless you want the very best full-drive performance. For 4.0 devices, which is most other portable gaming systems, the SN740 remains viable, particularly if you want the best performance at 2TB. However, future M.2 2230 and 2242 drives look to supplant the SN740 and SN770M by offering equal or better performance at up to 2TB or more. These drives, like the existing TLC-based options that top out at 1TB, will be more efficient and cool-running than the SN740, which should be factored into any purchase decision.

The WD SN740 is an OEM drive with a decent capacity range, from 256GB to 2TB. This allows more flexibility than the retail Black SN770M, which starts at 500GB, though most gaming portables would be better off with a higher capacity. There's also a small difference in marketed capacity, for example between 500GB on the SN770M and 512GB on the SN740. This is due to the SN740 having less overprovisioning, which does mean that it will have more user space available. This should not significantly impact performance or endurance.The SN740 is an OEM drive so pricing will vary, but you can find a rebranded SN740 2TB on Amazon for $159. We purchased our test drive from AliExpress for $122, if you're willing to go that route. Either way, it's typically less expensive than the WD Black SN770M 2TB at $209 — with the drawbacks of not being a retail part and the lack of a manufacturer warranty.The SN740 mostly performs the same as the SN770M, or the desktop M.2 2280 WD SN770 for that matter. Sequential performance tops out at 5,150/4,900 MB/s for reads / writes and the drive can hit up to 740K / 800K random read / write IOPS. Things deviate with the expected lifespan, as the SN740 has lower TBW at all capacities than its retail counterpart. This includes only 500TB written at 2TB, compared with 1200TB on the SN770M. Luckily, write endurance under warranty isn’t particularly important for this type of drive.Another place the SN740 deviates is with it having SKUs that support hardware encryption through Opal 2.01. This is optional as the base SKUs are only TCG Pyrite 2.01 compatible, so be sure to look carefully at the model number if you are seeking hardware encryption support.

The WD SN740 is an OEM drive, so normally you would not expect much if any software support. WD’s Digital Dashboard lists specific support for Black, or WD_BLACK, SSDs like the Black SN770 and SN770M. The SN740 has the same hardware, though, and the Digital Dashboard does work with other SSDs.WD also offers an OEM version of Acronis True Image but this also specifies Black SSDs. Luckily, there are free applications available for imaging and cloning if that doesn’t work for you. If you want to be completely sure about your drive being supported, buy a retail SN770M or a vendor-supported SN740.

Our SN740 sample is “SDDP” which indicates it does not support TCG Opal. This can be verified on WD’s site. This drive comes in both M.2 2230 and 2280 forms as well, so if you’re looking for encryption in the latter form factor you can get that with the SN740. In all cases, the drive is single-sided.The label indicates the drive could pull up to 8W or more, but WD rates it for 6.3W peak and the highest power state by SMART is 5.4W. We’ll check in on the power consumption later in our testing.

The SN740 has an SSD controller and a single NAND flash package, without any DRAM present. It’s not common to find DRAM on M.2 2230 drives unless it’s part of an embedded package. That makes hitting 2TB more difficult, particularly with TLC flash, but DRAM is not explicitly required for SSDs. When physical space and simplicity are at a premium, this can be a worthwhile trade-off.The 2TB SN740’s flash package has sixteen 1Tb BiCS5 dies. These are special BiCS5 dies with an interface speed of 1600 MT/s, allowing the SN740 to hit up to 5 GB/s or more with just a four-channel controller. This isn’t as exciting as it used to be, as there are now faster drives in this segment, but it’s more than enough to saturate a PCIe 3.0 device like the Steam Deck.This hardware is the same as found on the popular SN770 and SN770M, and while powerful it's also starting to show its age. In particular, the SN740 is not as cool-running or as power-efficient as drives using newer hardware. This is more of a concern when packed into a small form factor designed for a portable device.

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Current page:WD SN740 Features and Specifications

Shane Downing is a Freelance Reviewer for Tom’s Hardware US, covering consumer storage hardware.

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