WD Black SN750 NVMe SSD 1TB review: A little here and there

WD Black SN750 NVMe SSD 1TB Detailed Review

The WD SN750 is the third edition of the WD Black lineup of M.2 SSDs. Last year, we saw the 2018 WD Black SSD, which turned things around for WD and established the drive as the go-to enthusiast drive. This was a marked improvement over the first generation of WD SSDs that couldn’t differentiate themselves from the hundreds of other SSDs on the market. This was mainly due to the new proprietary controller which featured WD’s vertical integration. With the SN750, we should see another high-performer, as they’ve stuck with the same proprietary controller and even the same 64-layer 3D TLC NAND. We’re probably looking at a revision of the controller with better firmware in this new SN750 package. One thing that stands out with the SN750 is the massive EKWB heatsink it comes with. Variants without heatsink are also available.

WD Black SN750 NVMe SSD 1TB Specifications

WD didn’t share any controller specifications. Comparing the spec sheet side-by-side we can see that practically all the specifications are the same except for the read and write features. This would indicate that most of the improvements with this SKU are contained in the firmware. Rated Sec. The read speed has improved to 70 Mbps and rated sec. The write speed has increased to 200MBps. The Random Read and Write IOPS figures also show incremental improvements.

The 2018 WD Black was only available in 250GB/500GB/1TB variants while the 2019 SN750 now has a 2TB option as well. As per the rated specifications, the 1TB SKU, which we also have, seems to be the best performer. Let’s take a look at the specifications of this particular SKU.

construction and design

The first thing you notice about the WD Black SN750 is the heatsink. The need for a heatsink is often debated in analyst circles and the answer lies in how and where the SSD is installed. If there is a lot of accidental air-flow, the threshold for thermal throttling is rarely achieved by most users, if not, there is a very realistic possibility of SSD throttling. You may want to check the clearance of the WD Black before installing it on your motherboard as it is quite a tall heatsink. The SSD is 8.10mm tall with the heatsink installed and also the fact that once it’s installed, it will sit a bit higher on the motherboard as there’s a slight clearance under the M.2 port.

As a result, if your M.2 slot sits right below the graphics card, it may apply some pressure when the graphics card sags in the slot. A graphics card without a fancy shroud should ideally have no contact once installed, but we’ve seen some graphics cards in which a heatpipe from the heatsink assembly protrudes slightly from the bottom of the card. It intersects with the space in which the SSD is installed. In fact, motherboard manufacturers have already solved this problem by providing SSD heatsinks that are supported by separate mounts that prevent any pressure from being transferred to the SSD.

The heatsink wraps around the SSD as you see in the image above. So you not only have extra height but also a slight increase in width. Putting the two together is actually problematic for some motherboards. WD is addressing this by putting up a compatibility list on their website detailing which boards are compatible and which are not with boards that will require the heatsink to be removed before installing.

Finally, the heatsink is a massive slab of aluminum with V-shaped grooves cut into it. While it’s undoubtedly stylish and merges with the aesthetic of most motherboard designs, it’s not as effective as a proper fin-stack heatsink, but considering the application scenario, it seems appropriate.

Once you remove the label, the underlying PCB is indistinguishable from the 2018 WD Black SSD. It is a single sided PCB with the controller, NAND and RAM being the same. So WD hasn’t changed anything in the SN750.

Overall, the WD Black SN750 keeps the configuration the same but has a new heatsink which seems to be a concern when paired with some motherboards.

Display

You may be wondering if there will be any performance difference if the controller as well as the NAND chips are kept the same, and firmware is the major differentiator. You’d be surprised what can be achieved with just software/firmware tweaks. When we take a look at CrystalDiskMark, which is a very simple and synthetic benchmark that shows raw read and write speeds, you don’t see any major improvements. CrystalDiskMark can hardly bring out the specifics of firmware improvements but we have anyway because it happens to be popular. The performance numbers seem close to the spec sheet ie around the 3470MBps mark for read speeds and 2800MBps for write speeds. There isn’t much to explore here.

Moving on to analyzing driver performance after conditioning, we begin to see differences between the WD Black 2018 (SN700) and the WD SN750 emerge.

sequential read performance
The WD SN750 scored better than the WD Black SN700 in our continuous 128K read test by a considerable margin of about 360MBps. This puts it very close to the Intel 900p and the Corsair MP510 which are both excellent performers in their own right. Samsung’s 970 EVO is comparable but it should be noted that our 970 EVO was a 512GB SKU and not a 1TB SKU as we test.

sequential write performance
Also in the sequential write performance test we see the WD750 show an improvement of around 480MBps which is pretty big. It turns out that the firmware from WD actually outperforms in all the parameters that matter most.

SSD performance is no longer just about pure read speed or write speed. All new controllers are quite capable of handling synthetic loads quite easily which leads to metrics that are not indicative of real world performance. So we are going to take a look at the latency times for each operation at different queue depths.