The Western Digital WD Black 3D NAND SSD Review: EVO Meets Its Match
by Ganesh T S & Billy Tallis on April 5, 2018 9:45 AM EST- Posted in
- SSDs
- Storage
- Western Digital
- SanDisk
- NVMe
- Extreme Pro
- WD Black
Random Read Performance
Our first test of random read performance uses very short bursts of operations issued one at a time with no queuing. The drives are given enough idle time between bursts to yield an overall duty cycle of 20%, so thermal throttling is impossible. Each burst consists of a total of 32MB of 4kB random reads, from a 16GB span of the disk. The total data read is 1GB.
The burst random read performance of the WD Black isn't exceptional, but it is an improvement over the original WD Black SSD and is only slightly behind the Samsung 960 EVO.
Our sustained random read performance is similar to the random read test from our 2015 test suite: queue depths from 1 to 32 are tested, and the average performance and power efficiency across QD1, QD2 and QD4 are reported as the primary scores. Each queue depth is tested for one minute or 32GB of data transferred, whichever is shorter. After each queue depth is tested, the drive is given up to one minute to cool off so that the higher queue depths are unlikely to be affected by accumulated heat build-up. The individual read operations are again 4kB, and cover a 64GB span of the drive.
The sustained random read performance of the WD Black is a small improvement over last year's model, but not quite enough to catch up to Samsung. In addition, the recent Intel 760p also comes out slightly ahead of the WD Black.
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| Power Efficiency in MB/s/W | Average Power in W | ||||||||
The power efficiency of the WD Black during random reads is better than any other TLC drive as it barely draws any more power than a SATA drive during this test.
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At higher queue depths, the Samsung drives build a small performance lead over the WD Black, but most other drives fall far behind as the queue depth increases.
Random Write Performance
Our test of random write burst performance is structured similarly to the random read burst test, but each burst is only 4MB and the total test length is 128MB. The 4kB random write operations are distributed over a 16GB span of the drive, and the operations are issued one at a time with no queuing.
Our WD Black sample oddly returned a substantially better burst random write score than the SanDisk Extreme PRO that should be identical. Since both scores are at the top of the chart, unusually high variance doesn't actually present a problem.
As with the sustained random read test, our sustained 4kB random write test runs for up to one minute or 32GB per queue depth, covering a 64GB span of the drive and giving the drive up to 1 minute of idle time between queue depths to allow for write caches to be flushed and for the drive to cool down.
The new WD Black offers top-tier performance on the sustained random write test, well ahead of Samsung's current retail offerings and just barely behind the PM981 OEM drive that Samsung's next generation retail drives will be based upon. Last year's WD Black was just barely faster than SATA drives.
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| Power Efficiency in MB/s/W | Average Power in W | ||||||||
The overhaul of the NAND and the controller has taken the WD Black from the bottom of the efficiency chart with last year's model to the very top, where it has a small lead over the Toshiba XG5 and Samsung 960 PRO.
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The WD Black's random write performance saturates at QD4 while the Samsung drives and several other models continue improving and can hit much higher performance levels at high queue depths. However, the WD Black has all the random write performance it needs at the more important low queue depths.
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Cooe - Friday, April 6, 2018 - link
This is why the 250GB 960 EVO (and inevitably for the new WD Black as well) is far and away the most popular SKU just about everywhere. At around $110-120 vs $80-90, you're only paying a premium of around 20-25% over an equivalent tiered SATA III drive (ala an 850/860 EVO), though yes, you are sacrificing your sequential write speeds past the 13GB Turbowrite cache to just 300MB/s to get that comparatively tiny price premium for good NVMe vs SATA-III ratio.Tbh though in most general consumer PC workloads the above simply isn't an issue, as sustained writes of >13GB are few & far between, and the cache turnover speed while idling is speedy quick. I think this is exactly the reason why Western Digital & SanDisk adopted the kind of handicapped nCache 2.0 into a very Turbowrite-esque system with nCache 3.0 (but more like 850 EVO's simplier static TW cache just a lot bigger, rather a dynamic one like the 960 EVO uses).
Dragonstongue - Thursday, April 5, 2018 - link
competition is good, but not if they all want to keep pricing within a few $ of each other IMO.for nvme/M.2 drives they need to make sure is more universal that it is more plug and play so consumers can be assured it will work on their motherboard as a bootable OS drive right off the bat without driver specific support (quite a few drives quite a few no matter on Intel or AMD chipset seem to have this issue hence they need more plug and play support)
costs more than a normal sata based one (performance is much higher though that does not always mean can see this difference) but having to screw around making the bios/windows able to use the drive in question sucks (not saying this is a problem with this specific model, but it is a problem)
nice write up though ^.^
PeachNCream - Thursday, April 5, 2018 - link
I agree with you on pricing. It would be good if WD had priced their drive a bit lower in order to force Samsung to respond since they have a competitive product, but they have to get a return on development costs so it's safe for them to match Samsung's price. I don't like it because the consumer isn't realizing a benefit in additional competition if neither company budges on cost, but I can understand the business justifications that are probably behind it.Cliff34 - Thursday, April 5, 2018 - link
What I do wish is that the m2 sata drives should be the same price as sata ssd. After all, the specs are the same just diff forms. Too bad for us consumers.The_Assimilator - Friday, April 6, 2018 - link
M.2 SATA drives should cost *less* than their 2.5" equivalents, and the 2.5" drives should simply be an M.2 drives in an enclosure with an M.2-to-SATA connector.Cliff34 - Saturday, April 7, 2018 - link
It should but it doesn't. My guess is because m2 form is a niche market because most computer accept SATA. Therefore, companies can charge more because they can get away with it. Unless there's a huge swing of adoption of m2 form for desktop and laptops, m2 will always cost more than SATA.zodiacfml - Friday, April 6, 2018 - link
True.wr3zzz - Thursday, April 5, 2018 - link
WD's pricing strategy is probably indicative that current demand for NVMe is still outpacing supply.Arbie - Thursday, April 5, 2018 - link
Great article and follow-up analysis of the tests; thanks.iwod - Thursday, April 5, 2018 - link
What are the difference in real world usage? We thought we needed better QD1, and even that doesn't return any significant difference in optane.