June 21, 2024


Sapiens Digital

WD Blue SN550 (1TB) – Review 2020

9 min read

Launched as a follow-up to last year’s WD Blue SN500, the WD Blue SN550 (starts at $54.99 for 250GB; $99.99 for our 1TB test model) is a respectably quick, highly affordable M.2 NVMe SSD that challenges other drives up to twice its cost in performance and speed. The drive is a leader in its price class, as both a solid workhorse that can handle daily content-creation tasks in programs like Adobe’s key creative applications, while also holding its own in gaming tests and raw sequential throughput. This DRAM-less SSD (more on that later) may not be the right choice for anyone who needs tons of write-durability, relative to other drives, but for the rest of us, it’s a solid pick for the price. (Note: At this writing, the 1TB version was selling from most etailers for 20 percent above its MSRP.)

An Evolution of the Blue

WD Blue is Western Digital’s more value-oriented, mainstream SSD family, in contrast to the more performance-oriented, hardcore WD Black series. Still, it’s no slouch on the specifications front.

WD Blue SN550 top of drive

The WD Blue SN550 is an M.2 Type-2280 PCI Express 3.0 x4 NVMe SSD, based on a second-generation, 96-layer 3D TLC NAND manufacturing process. (Check out our SSD dejargonizer if you need help unraveling that ball of acronyms.) This 80mm-long drive comes in three storage-volume sizes: 250GB, 500GB, and 1TB. Western Digital rates the 1TB variant of the drive (the one we’re testing here) for peak throughput of 2,400MBps on sequential reads and 1,950MBps on writes, and it carries a five-year warranty. Here’s a summary of the available capacities.

WD Blue SN550 Configurations

One of the main upgrades from the older SN500 model that we tested last year is the increase in PCI Express lane allocation, which directly affects peak throughput. The WD Blue has gone from two lanes (PCI Express x2) in the previous model, a decidedly budget move, to four (PCI Express x4) in the SN550. That helps boost the top sequential read and write speeds from the SN500’s 1,700MBps and 1,450MBps, respectively, to the SN550’s numbers cited above.

The higher lane allocation puts the SN550 on par with most other mainstream M.2 drives nowadays. One place I’d like to see a bit more muscle, though, is in the terabytes written (TBW) rating. For example, the Editors’ Choice-winning Addlink S70 almost exactly doubles the TBW rating of the WD Blue SN550, while costing only roughly a third more. This doesn’t mean the WD Blue SN550 is a poor value, per se, just that it may not be the right choice for write-happy users, such as content creators who scribe lots of gigabytes of data per day to their drives. 

DRAM? Where We’re Going, We Don’t Need DRAM

As I alluded to in the introduction, the WD Blue SN550, like many other cheap SSDs, is a DRAM-less drive. For starters, let’s define what DRAM is in an SSD context and what it’s used for.

In a traditional SSD with DRAM, the data that you’re keeping is stored on the NAND flash chips that sit on the drive’s printed circuit board (PCB). The data isn’t static, though, and is constantly being moved around by the drive to ensure that no cells are being taxed much more than others and therefore wear down unevenly. This is a process called “wear leveling.” 

Because the data is moved around frequently, some SSDs use a smidge of DRAM—which is much faster to access and read than NAND flash—to “map out” the data, and provide a reference point for the drive so it knows where everything is. 

Now, a drive can operate just fine without a DRAM chip installed. Instead, the “map” is stored either on the NAND flash chips themselves, or can be stored temporarily in the RAM of the system you’re booting into. From the SSD maker’s point of view, leaving off the DRAM saves on production cost, thereby making the drive cheaper to manufacture, and cheaper for consumers in the end. However, this can have a marked effect on drives that are used to store operating systems, programs, or games, all of which use shallow-depth 4K writes and reads. 

WD Blue SN550 M.2 connector

WD seems to have gotten around this hurdle with the addition of a much smaller SRAM chip (“static” RAM to DRAM’s “dynamic” RAM). SRAM chips are faster than DRAM, though they can be more expensive to implement. WD also found a workaround for this, including just a few megabytes of SRAM on the in-house Western Digital controller, rather than the larger SRAM caches that you might see on other drives that implement a similar technique.

With that bit of background out of the way, let’s get into the benchmarks to see how this DRAM-less SSD handles…

Testing the WD Blue: A Benchmark Duel

We test all of our PCI Express 3.0 SSDs on an Asus Prime X299 Deluxe motherboard with an Intel Core i9-10980XE processor clocked at a max boost frequency of 4.6GHz. We use 16GB of DDR4 Corsair Dominator RAM clocked to 3,600MHz, and the system is using an Nvidia GeForce RTX 2080 Ti Founders Edition as its discrete graphics card.

PCMark 10 Overall Storage Test

First, there’s the overall PCMark 10 Full System Drive Benchmark. This score represents how well drives do throughout the entire PCMark 10 run, and are the sanctioned scores presented by UL’s software at the end of each run. This score includes a weighted average of every simulated activity that the PCMark 10 storage test runs, from copying files to launching games, booting an OS to running creative applications. It’s a general indicator of how consistently a drive can perform through 23 different usage scenarios.

WD Blue SN550 PCMark 10 overall storage test

Overall, the WD Blue SN550 was well ahead of its cost-comparative competition, showing that its added lanes and high 4K random read speeds make it a great choice for all-around users.

Booting Windows 10

Next is a more granular measure derived from one of PCMark 10’s background “traces.” This and following PCMark 10-derived tests represent a simulation of how quickly a drive is capable of launching a particular program or booting Windows 10 by recording how many megabytes per second the drive is reading what are known as “shallow-queue 4K random” blocks of data (i.e., of the kind in which most applications, games, or operating systems are stored). While UL recommends using the overall “read/write MBps bandwidth” metric in these tests, instead we dug a bit deeper to only include random 4K bandwidth in order to paint what we believe is a more specific picture of how well a drive can perform in these tasks.

The first test is the Windows 10 boot trace, which simulates a full operating system startup procedure and records how quickly the drive is able to feed the data required for that task.

WD Blue SN 550 PCM10 Windows 10 Boot

In this test the WD Blue SN550 holds its own against pricier drives like the Patriot P300, while also keeping pace with performers like the Seagate and TeamGroup.

Launching Games

Next up is a game-launching set, which simulates how quickly a drive can read shallow-depth small random 4K byte packages. This is one of the more commonly used file sizes for game installations, though that composition does depend on the title you’re playing.

While the three games tested in PCMark 10 are primarily stored in small random 4K, tests from around the web have shown that MMORPGs can more often use the 16K file size, and other genres may go as large as anywhere from 32K up to 128K. However for the sake of these tests, 4K small random read is the most accurate metric to measure the launch speeds of three popular FPS titles: Battlefield 5, Overwatch, and Call of Duty: Black Ops 4.

WD Blue SN 550 PCM10 Game Launching

In these traces, the WD Blue SN550 regularly scores in the top tiers of its competitors when launching games like Overwatch or COD, though it lagged slightly behind more gaming-oriented drives like the Seagate FireCuda 510 and TeamGroup T-Force Cardea II in Battlefield 5.

Launching Creative Applications

Here the drives are put through a very important test for creative types. As anyone who regularly works in programs like Adobe Premiere or Photoshop can tell you, oftentimes the most excruciating part of the whole experience is the time it takes for the program to launch. There are a lot of elements that creative applications need to load.

However, it should be noted, that these two tests don’t tell the whole story of how a drive will perform for all creative applications. For example, cinema rendering programs like Cinema 4D may need to load dozens of different types of files at once, rather than just one large file like you might have encased in a Photoshop project or a movie that’s being edited in Premiere.

Depending on the complexity of your work and the number of elements in a scene, your software may have to load 3D models, sound files, physics elements, and more. The overall PCMark 10 score of a drive will tell a better story for how a drive built to handle these types of programs will do than these numbers alone. But they’re nonetheless interesting fodder for folks who live and breathe these Adobe apps.

WD Blue SN550 PCM10 Creative Applications

Most of the drives we tested scored fairly even here, to the point where you only might notice a difference between the WD Blue SN550 and the Cardea II in applications like Adobe Premiere Pro with a stopwatch.

Copy Tests

Finally come the copy tests. While at first these numbers might look low compared to the straight sequential-throughput numbers achieved in benchmarks like Crystal DiskMark 6.0 and AS-SSD, that’s due to the way this score is calculated.

Unlike those tests, which copy a file from another drive onto the testing drive and record the raw writing throughput to the drive (or reading capacity off of it to another drive), PCMark 10 is expressing the average bandwidth speed of a transfer when the file is on the same drive. If you’re regularly moving files around on your drive from one folder to another, this test is a handy relative throughput measure.

WD Blue SN550 PCMark 10 ISO and File Copy tests

Right out of the gate, the WD Blue SN550 proves itself as a very fast option (alongside the ADATA Spectrix S40G) if you’re regularly shifting around programs or ISO files of the kind in these PCMark 10 traces. JPEG copying was considerably slower, but still competitive for its cost.

Crystal DiskMark 6.0

Okay, off of PCMark 10 and onto a more traditional measure. The Crystal DiskMark 6.0 sequential tests simulate best-case, straight-line transfers of large files. Let’s get into the drag races. 

WD Blue SN550 CDM Sequential

Here the drive finally starts to falter against some other drives we tested, but it actually exceeds (by a smidge) its WD-rated speeds in sequential reads and writes.

In contrast, the utility’s 4K (or “random read/write”) tests simulate typical processes involved in program/game launching…

WD Blue SN550 CDM 4K

Here the drive is strong in 4K random write speeds, and competitive in random read.

AS-SSD Copy Tests

Last up is a series of file and folder transfers done in the SSD benchmarking utility AS-SSD. This trio of tests involves copying large files or folders from one location on the test drive to another…

WD Blue SN550 AS-SSD

Though it’s a bit difficult to put them up against one another 1:1 (the nature of the copied data is different in each case), the scores in the AS-SSD copy tests reiterate much of the same story we saw in the PCMark 10 run: the WD Blue holds its own.

When It’s Good to Be Kinda Blue

While the sequential results of the WD Blue SN550 may not look tip-top on the surface, it seems WD was more concerned with real-world performance in the development of this drive, rather than just peak scores in spec sheets.

Sure, it’s always nice to see bigger numbers for any specification you publish, but what does that actually mean for the people who buy and use the product? In this spirit, the WD Blue SN550 is a bit of a wolf in sheep’s clothing once you factor in the price, the 4K read and write speeds, and its competitive performance across the board in the PCMark 10 suite. Beyond the raw bandwidth numbers, it’s clear that the WD Blue SN550 is a great pick for all-around budget buyers who aren’t overly concerned about write-durability ratings.

WD Blue SN550 box and drive

As noted up top, prices have spiked a bit, to $119, for the 1TB SN550 since the original $99 MSRP of the drive was minted (a trend we’ve seen across the component space over the past few months), but this isn’t enough of a difference to tank the value of the drive outright. If you’re looking for a solid SSD that can do almost everything it promises at a respectable price point, the WD Blue SN550 is worth a second and a third look.

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