Western Digital is refreshing their NVMe-based WD Blue product line, replacing the WD Blue SN500 with the new WD Blue SN550. The SN550 updates both the controller and NAND, providing higher performance and capacity than the SN500.

The SN500 was Western Digital's first retail entry-level NVMe SSD, based on the OEM WD SN520. These drives use an in-house SSD controller based on the same architecture as the controller on their WD Black family (SN720/SN750), but with fewer channels, PCIe lanes and no external DRAM interface. The SN500 used the same PCB layout as the OEM SN520, which kept all the components within the first 30mm of the M.2 card, even though the SN500 is sold only as a M.2 2280 card rather than the variety of lengths the SN520 is available in.  

The SN500 impressed us with much better performance than we expected from a DRAMless NVMe SSD, and the power efficiency was also pretty good. The SN550 promises better performance enabled by a move up to four PCIe lanes, allowing sequential transfer speeds to now hit 2.4GB/s compared to 1.7GB/s for the SN500. That higher performance will drive power consumption up a bit, but considering that the SN500 rarely exceeds 2W, that's not a big problem for the SN550. However, WD is giving the SN550 an "improved thermal design" that appears to consist of just moving the NAND flash package to the far end of the M.2 card rather than keeping it right next to the controller. Even though the SN550 adds a 1TB option that the SN500 lacked, it still uses only one NAND flash package. That means that at least the 1TB model has to be using Western Digital's 512Gb TLC NAND dies.

WD Blue SN550 SSD Specifications
Capacity 250 GB 500 GB 1 TB
Form Factor M.2 2280 PCIe 3.0 x4
Controller WD in-house
NAND Flash Western Digital/SanDisk 96L 3D TLC
Sequential Read 2400 MB/s 2400 MB/s 2400 MB/s
Sequential Write 950 MB/s 1750 MB/s 1950 MB/s
Random Read 170k IOPS 300k IOPS 410k IOPS
Random Write 135k IOPS 240k IOPS 405k IOPS
Warranty 5 years
Write Endurance 150 TB
0.3 DWPD
300 TB
0.3 DWPD
600 TB
0.3 DWPD
MSRP $54.99 $64.99 $99.99

The WD Blue SN550 comes with the usual 5-year, 0.3 DWPD warranty, which is as good as can be expected for an entry-level drive. The initial MSRPs are on the high side, so these drives won't be reasonable purchases until prices come down a bit.

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  • Potato Power - Tuesday, December 10, 2019 - link

    If the prices and spec are correct. The 1TB version isn't a bad deal. However, the 250GB one makes very little sense.
  • timecop1818 - Tuesday, December 10, 2019 - link

    250GB will probably go into shit-tier netbook/chromebook type things for OEMs, friend got a 128GB SN520 in some acer netbook that was on sale for $150 or something. I'm sure the end price for OEM batch of these is way less than $50
  • bonehead123 - Tuesday, December 10, 2019 - link

    2 things come to mind here:

    "Cheap is as cheap does"

    "You only get what you are willing to pay for"

    Thanks but no thanks, I'll stick with my SN750 blacks, which I got on sale a while back for just a few more $$ than these, and just bought some more for just over $100 for the 1TB ones....
  • ksec - Tuesday, December 10, 2019 - link

    Low Power, Very Decent Performance, High Endurance. WD Branded; A little more Quality Assurance and Firmware support.

    Literally perfect for 90% of user, not sure why this is consider as on the high side. It is not a bargain for sure, but I see it as fair pricing.
  • p1esk - Tuesday, December 10, 2019 - link

    I want to buy a good NVMe 2TB SSD. I the past I have only bought Samsung SSDs. Just looked at the prices, and I see that Samsung 970 EVO PLUS costs $400, while SIlicon Power (top recommendation on AT) is $250. Why is that? I'm not concerned with speed - any NVMe drive is probably fast enough, but I want the most reliable one.

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