WD Blue SN550 1TB Review: Affordable NVMe Performance

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WD Blue SN550The WD Blue SN550 is the latest (2020) variety in Western Digital’s Blue range of M.2 SSDs. It replaces last year’s SN500, which was only available in 250GB and 500GB capacities. It should also not be confused with the similarly-named WD Blue 3D NAND, which is a significantly slower SATA SSD in the M.2 form factor. This doesn’t change the fact that WD has used the Blue label for its value/mainstream storage products for many years, and the SN550 is no exception.

Introduction: WD Blue SN550 1TB

At around $100 for the 1 TB capacity, the WD Blue SN550 is not intended to compete with the best M.2 NVMe SSDs like the WD Black SN750/SN850 or Samsung’s PRO/EVO lineup. Instead, it challenges other entry-level NVMe drives such as the QLC-based Sabrent Rocket Q, Intel 665p, and Crucial P1. However, the WD Blue SN550 uses higher-end 96-layer TLC NAND from WD’s subsidiary SanDisk.


WD Blue SN550250GB
Form FactorM.2 2280M.2 2280M.2 2280
PCIe 3.0 x4/
NVMe 1.4
PCIe 3.0 x4/
NVMe 1.4
PCIe 3.0 x4/
NVMe 1.4
ControllerWD ProprietaryWD ProprietaryWD Proprietary
MemorySanDisk 96L TLCSanDisk 96L TLCSanDisk 96L TLC
Sequential Read2,400 MB/s2,400 MB/s2,400 MB/s
Sequential Write950 MB/s1,750 MB/s1,750 MB/s
Random Read170,000 IOPS300,000 IOPS410,000 IOPS
Random Write135,000 IOPS240,000 IOPS405,000 IOPS
Endurance150 TBW300 TBW600 TBW
Warranty5 Years5 Years5 Years

As this is an entry-level drive, the WD Blue SN550 has to make do without a DRAM buffer and its specifications are not comparable to high-end PCIe/NVMe SSDs. On the other hand, it is still about four times as fast (theoretically) as any SATA SSD – while actually being slightly cheaper than some of the popular 2.5″ SATA alternatives. That makes the SN550 and other affordable NVMe SSDs attractive for anyone with an M.2 slot to spare.

WD Blue SN550 1TB Benchmarks

Synthetic benchmarks are always interesting, but from a user experience perspective, they will not tell you all that much about perceived performance. Although they are usually the main selling point for high-end NVMe SSDs, very high max. sequential transfer rates will not be a deciding factor for the user experience in an average office or gaming PC. User workloads are typically a complex mix of random and sequential access patterns. For this reason, we try to use a mix of benchmarks with an emphasis on user-centric tests.


AS SSD scores tend to be relatively inconsistent, but it’s still a useful tool for measuring transfer rates with incompressible data. As you might expect, the WD Blue SN550 is not topping the charts as far as sequential transfers go, although the difference is far less dramatic in the more important 4K area.


CrystalDiskMark is another lightweight tool that measures sequential performance as well as random performance at different queue depths. Again, the WD Blue SN550’s sequential read transfer rate struggles to keep up with the compared drives (as it should, based on the specifications). In the 4K tests, the SN550 compares more favorably to the other drives, except for the much more expensive and PCIe 4.0-enabled SN850.

Response Times/Latency (Anvil’s Storage Utilities)

The importance of low latency is highlighted by the fact that Intel’s Optane (3D XPoint) SSDs are still well ahead of the competition in many mixed workloads. This results in improved performance where it counts, such as in loading times and other areas that affect the user experience. Here, the SN550 is mostly in line with the other PCIe 3.0 drives.

Loading Times (PCMark 10, FF XIV)

When comparing loading times with different SSDs, the differences are often surprisingly small, indicating that the bottlenecks may be found elsewhere in the system. To test loading times without having to resort to a stopwatch, PCMark 10’s app start-up (cold start) should be fairly indicative of what to expect in the real world.

Unsurprisingly, the high-end Gen4 WD Black SN850 is the undisputed winner, but the significantly cheaper WD Blue SN550 is actually not far behind. It is also marginally faster than the more expensive Samsung 980.

The Final Fantasy XIV Shadowbringers benchmark loads five different scenes/levels and provides a total loading time. A mechanical 7,200 rpm 3.5″ hard drive has been added for perspective. Once again, the SN550 is second only to the SN850.

Conclusion: Great Entry-Level PCIe/NVMe SSD

WD Blue SN550Considering that the cost per GB is about half that of current performance leaders such as the Samsung 980 PRO and the WD Black SN850, there is no question that the WD Blue SN550 offers great value. Although some synthetic benchmarks may tell you otherwise, performance in most real-world office or gaming scenarios is a lot greater than the different specifications imply.

Also, you are essentially getting a PCIe/NVMe drive for just slightly more than the price of an average 2.5″ SATA SSD. And thanks to the TLC (triple-level cell) NAND, it’s also noteworthy that the endurance rating is comparable to the high-end alternatives at equivalent capacities. This is usually not the case with other affordable alternatives based on less durable QLC (quad-level cell) NAND.

If you are looking for a fast NVMe boot drive within a similar budget, your choices right now are either an entry-level 1TB drive like this one or a high-end 500GB SSD like the Sabrent Rocket Gen4 (PCIe 4.0) or Samsung 970 EVO Plus (PCIe 3.0). If you opt for the former, the SN550 looks like one of the best alternatives at this point.

8.5Expert Score
Affordable NVMe Performance

The WD Blue SN550 Rocket Q offers considerably improved performance for about the same price as the WD Blue SATA model.

  • Excellent value
  • High endurance rating
  • More than decent real-world performance
  • No 2TB version
  • Less impressive sequential performance

Jesper Berg

As a PC gaming enthusiast since the 3dfx Voodoo era, Jesper has had time to experiment with a fair few FPS-improving PC parts over the years. His job at GPCB is to test and evaluate hardware, mainly focusing on GPUs and storage devices.

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