Western Digital Black SN750 SSD Review

1. Introduction, Specifications, and Pricing
2. 1TB Class Performance Testing
3. 1TB Class Real-World Performance Testing
4. Final Thoughts

TweakTown's Rating: 91%

The Bottom Line

WD didn't add much to the version we tested today but the heat sink model coming soon should standout in this highly competitive market.

Introduction, Specifications, and Pricing

Western Digital and manufacturing partner Toshiba have talked about the benefits of 96-layer TLC (BiCS4) for some time now. Toshiba just announced its second product to use the new memory, BG4, while Western Digital has largely ignored the new media's availability.

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The new WD Black SN750 SSD uses the same BiCS3 64-layer TLC memory as the previous generation Black SSD and the same in-house controller. The company updated the product name with a differentiator finally, that's where the SN750 comes from. The new Black NVMe SSD also received new programming, essentially a firmware update, and snazzy graphics that should appeal to the eSports and millennial generation.

It's easy to swallow Western Digital using the same controller on the 2019 flagship SSD. With full controller of the design, it's easy to make significant changes from one release to the next and still see performance improvements. Samsung has used the Phoenix controller for a few product generations now, and it's even under the heat sink on the Optane competitor, 983 ZET, one of the fastest enterprise SSDs shipping today.

The flash is what we're stuck on. BiCS3 carries a bus speed of 400 to 533 MT/s. BiCS4, AKA 96L, improves bandwidth to 667 to 800 MT/s, the same bus speeds as Micron's impressive 64L TLC that powers SN750's strongest competitors.

Specifications

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The new Black is the third NVMe SSD to carry the name from Western Digital. The company changed the names in small ways for the first two models but largely advertised as The WD Black, just like the hard disk drives. To get around the confusing name, WD added the SN750 model number to the name.

The new series ships in four capacities from 250GB to 2TB with the largest shipping in February. The Black SN750 will arrive in two versions, the one we're testing today with a single-sided design and an enhanced model with a heat sink designed by EK. The enhanced version will not ship in the 250GB size.

Western Digital gave us an impressive presentation for the new heat sink enhanced model, but we will need to save that for another review due to the rapidly approaching embargo lift. More on that model when the drive arrives for testing.

The Black SN750 uses WD's custom in-house controller with new programming. This is the same controller first used on the Black released in 2018 and a series of OEM drives released around the same time. As we mentioned, WD also chose to use proven BiCS3 TLC memory with this series, like the previous release.

The new programming bumps performance up to 3,470 MB/s sequential reads for the 1TB model we are testing today and 3,000 MB/s sequential writes. Random performance increases to a smashing 515,000 IOPS read and 560,000 IOPS write. These numbers come from enterprise-derived tests under optimal conditions for testing rather than consumer-focused real-world workloads.

Pricing, Warranty, and Endurance

WD's flagship NVMe SSD carries a premium price. The Black SN750 starts at $79.99 for the 250GB model, and that moves steadily to $499.99 for the 2TB drive. The 500GB is a more affordable $129.99 and the 1TB model we're testing today costs $249.99. All pricing came from WD in the form of manufacturers suggested pricing, so we expect to see these drives a little lower at Amazon and Newegg.

This series carries a premium 5-year warranty and a generous endurance rating. The 250GB model comes with a 200 TBW warranty, more than most 256GB class SSDs shipping today. The 500GB only increases the endurance to 300 TBW, but that doubles with each model after to 600 TBW and 1,200 TBW.

Value-Add Accessories

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With this release, Western Digital updated the graphic interface of the aging SSD Dashboard software. The new SN750 gets a unique feature with Dashboard in the form of a virtual toggle switch. The switch controls a feature called Game Mode.

Game Mode disables the drive's reporting to the operating system for power states 3 and 4, the low-power modes. When enabled, the drive advertises support for only PS0. At the same time, Game Mode eliminates the entrance of device side low-power states.

When an SSD moves into a lower power state, it needs to wake up before processing data. The deeper the sleep state, the longer it takes to wake up the device. The difference in this case is like a soldier standing at the read with a weapon in his hand as opposed to one in the mess tent having lunch.

The WD Dashboard is one of the more useful software tools. It also features a unique real-time performance monitor that we've yet to see in any other Toolbox like software. The usual tools and features, such as firmware updating, drive status and monitoring round out the suite. Another unique feature is the advertisements that scroll on the right side of the utility. We could do without this feature.

A Closer Look

We love the new look of the WD Black series. It's a modern twist on a historic flagship series with a strong following.

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Inside the package, we found our drive secure in the form fitted plastic case. A paper manual that details the warranty contact information is also included.

The drive under the microscope today uses a single-sided design with one controller, one DDR4 and two NAND packages. All four capacities use the same single-sided design so it will work on the Lenovo Yoga and a handful of other notebooks that will not accept components on both sides due to size restraints.

1TB Class Performance Testing

Product Comparison

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The charts show all of the next generation 1TB NVMe SSDs shipping today. The 2019 releases include the new WD Black SN750, ADATA SX8200 Pro, HP EX950 and the MyDigitalSSD BPX Pro that came to market at the tail end of 2018.

In the last couple of reviews, we've looked for the SanDisk Extreme Pro and WD Black (the previous generation) but had a difficult finding the drives. That indicated to use a new model was coming in the near future. We used the SanDisk Extreme Pro in the charts, but the performance is identical to the previous generation Black. We rounded out the charts with the Plextor M9Pe add-in card, Samsung 970 EVO, and 970 Pro. We updated all pricing 24 hours before publishing the review.

Sequential Read Performance

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The 1TB Black SN750 brings with it the same dip at queue depth 2 (QD2) that we observed on the previous generation as well as the products using the Phison E12 controller. We massaged the test a bit to get a better result much as we did with the MyDigitalSSD BPX Pro, but we couldn't make it go away completely with our test script. Instead of focusing on the QD2 sequential read performance here, we will focus on performance in the sequential mixed workload test towards the bottom of this page.

Sequential Write Performance

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The sequential burst write performance with the new Black SN750 is more consistent compared to the previous model from WD. The QD1 performance is a little higher but the QD2 performance is nearly identical.

Sustained Sequential Write Performance

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Moving past the burst sequential writes, here we see a long 128KB write to the entire user area of the SSD. The 1TB Black SN750 burst speed is slightly higher than the previous generation, and the sustained write speed is higher as well. We observed some severe dips starting around 45% of the way through the test. This is after nearly 500GB of data written to the drive without a break, so we don't have any real concerns about this affecting users.

The data "folding" from the SLC to the TLC area likely causes the dips. Some companies choose to fill the SLC area and then write data directly to the TLC, but the Black SN750 moves all data to the SLC first. When the data moves to TLC, it causes a small performance dip during the process.

The dips could also be the result of thermal throttling. The SN750 with a heat sink, set to arrive in a month or so, will let us know for sure. Both folding data and thermal throttling can appear the same in extended write tests precisely like this.

Random Read Performance

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The all-important random read test....where to start. For the last few weeks, we've talked about the incredible low queue depth random read performance from drives with Micron's 64L TLC and Silicon Motion controllers. WD uses SMI controllers for some downmarket products, but the flagship Black series uses an in-house controller.

The new Black with the 2019 optimizations scores 10,725 IOPS at QD1, around 575 IOPS more than the previous generation in our testing. Using Anvil Disk, we scored just over 12,000 random read IOPSs at QD1, but the other drives also score higher in that test due to the sequence we run.

The important takeaway from the random read test is that the new Black SN750 is only slightly faster than the previous generation in this particular area and not much quicker than the best SATA SSDs shipping today like the Crucial MX500. This will carry over to many of the applications tests on the next page and in the user experience; you will feel at home with this drive.

Random Write Performance

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The Black SN750 does perform very well with small block size random data writes. The drive is faster at low queue depths compared to the other modern drives in the charts today. These are burst tests absorbed by the SLC buffer and not sustained writes where the data folds into the TLC area.

70% Read Sequential Performance

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We have to rely on the mixed workload test to get a better understanding of the low queue depth sequential read performance due to the odd error we get with some next-generation NVMe controllers running 100% reads.

The new 1TB Black SN750 scores lower than the previous generation drive at QD2 but quickly joins the Extreme Pro NVMe with a similar slope through the higher queue depths in this test using 128 KB blocks and a 70% read.

70% Read Random Performance

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In the random mixed workload test, we see a slightly higher performance reading from QD2 to QD8. The new 1TB Black SN750 starts to leap ahead of the previous generation NVMe drive from WD/SanDisk between QD8 and QD16. The new drive continues its lead with a single worker through the rest of the test.

1TB Class Real-World Performance Testing

Game Load Time

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We a lower queue depth 1 and 4 random read performance compared to many of the other drives in the charts today, we don't expect the 1TB Black SN750 to break any performance records with applications.

In the Final Fantasy: STORMBLOOD game level load time test the 1TB Black SN750 scored 14.149 seconds. The drive took less than 2 seconds longer to load the levels compared to the HP EX950 we tested just days ago. We observed a slight performance increase over the SanDisk Extreme Pro NVMe and both WD/SanDisk SSDs outperformed the aging Samsung 970 EVO by a second or more.

PCMark 8 Total Storage Bandwidth

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The PCMark 8 Storage Bandwidth suite runs nine commonly used applications for ten tests to gauge performance across a wider range of software. The WD Black SN750 scores 508.65 MB/s on average with the ten tests. In WD's lab, the 1TB SN750 scored around 100 MB/s more but the company also uses a newer version of the test. We use an older version that allows us to compared previously tested products.

PCMark 8 Extended Storage Test

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The PCMark 8 Extended Storage Test uses the same nine applications but preconditions the drives to show heavier workloads from more data written to the flash in a shorter amount of time. The recovery phases of the test inject a 5-minute pause between each run of nine tests to allow the drives to recover (perform background data management). None of the TLC-based SSDs performs as well as the Samsung 970 Pro, the only model on the charts with MLC flash.

SYSmark 2014 SE System Responsiveness and Power Tests

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The SYSmark 2014 SE test is the first to measure what we commonly refer to as the user experience. The technical term is called system responsiveness. This is the amount of time it takes from requesting an action to when the it starts. The pause between those two actions is usually so small that we don't chart the data. This test changes the microseconds of latency into a weighted score. The base score is 1,000 and that comes from a specific system with an OEM version of Samsung's 850 EVO.

The new 1TB WD Black SN750 delivers slightly better system responsiveness compared to the 850 EVO but trails all of the other next-generation NVMe SSDs.

Notebook Battery Life

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At one point in the testing process, we were under the impression that Game Mode changed Windows settings and not the drive itself. This inadvertently led to testing the Black SN750 in our notebook battery life test with Game Mode enabled. If you pull the drive from your desktop to run it in a notebook, be sure to install the software to disable Game Mode.

With device side low-power states enabled we gained a significant amount of "on battery" time with BAPCo's MobileMark software and our Lenovo Y700-17 gaming notebook. The increase was not enough to push the 1TB Black SN750 into the upper half of the chart, but it did make a difference.

Final Thoughts

In its current form, the new WD Black SN750 is a lackluster NVMe SSD for enthusiasts looking for innovative components and next-generation performance. WD simply left performance off the table by choosing the same hardware components we saw last year on a product that was quickly overrun by competing products that came to market around the same time. Those companies managed to squeeze even more performance out of the new 2019 designs with the same 2018 (64L Micron) flash, but actually found performance in the controller by making changes to the data path (SMI SM2262EN)

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The Black SN750 also found some performance, but the outcome is much more reserved than we expected to see. The Black name started with hard disk drives and the performance improvements observed would be great on those products. A few percentage points here and a few there is common on HDDs but flash-based increase using come in more significant bursts, a real reason to upgrade year over year.

The two largest reasons to upgrade to the Black SN750 come from the increased capacity, if you can afford the $499.99 asking price for the 2TB option. Game Mode is also a nice feature but you can get most of the way there by manipulating Windows. In our testing Game Mode only increased performance in our notebook battery life test (and hurt battery life). Our other systems already run heavy Windows power optimizations to achieve the highest performance. Dashboard does allow you to manipulate drive side power state, not an easy task from Windows.

When it comes to pricing, there are certainly faster next-generation models shipping today that cost less. The HP EX950 we tested just a few days ago is a strong example. It features similar endurance, improved performance, and in the 2TB model costs $100 less.

We really wish WD released the EK heat sink version before the vanilla model. The heat sink adds a new element to the mix, increases the overall value and does more to enhance the "gamer" focus. Most gamers put M.2 SSDs in the slot under the video card, and the heat sink goes a long way to taming temperatures in a space with minimal airflow. Depending on the added cost (if any), the Black SN750 with the EK solid aluminum heat sink should be more appealing for desktop use and the target audience. There is just not enough SN750 in the new Black NVMe SSD to make the base model an interesting product for many of our readers.