The Western Digital WD Black 3D NAND SSD Review: EVO Meets Its Match

AnandTech Storage Bench - Light

Our Light storage test has relatively more sequential accesses and lower queue depths than The Destroyer or the Heavy test, and it's by far the shortest test overall. It's based largely on applications that aren't highly dependent on storage performance, so this is a test more of application launch times and file load times. This test can be seen as the sum of all the little delays in daily usage, but with the idle times trimmed to 25ms it takes less than half an hour to run. Details of the Light test can be found here. As with the ATSB Heavy test, this test is run with the drive both freshly erased and empty, and after filling the drive with sequential writes.

The WD Black's average data rates on the Light test are slightly slower than the Samsung 960 EVO when the test is run on an empty drive, and a bit faster when the drive is full. The Samsung PM981 is the only drive that has a clear lead in both cases, and even then it isn't a very big margin. The worst-case performance here from the new WD Black is substantially faster than the best-case from last year's WD Black.

The average latencies from the WD Black during the Light test are as low as any SSD offers. The 99th percentile latencies are not quite as fast as Samsung's best drives offer, except that the full-drive performance is better than the 960 EVO.

There are quite a few SSDs with average read latency scores that are close to or slightly better than the WD Black, and even the low-end NVMe SSDs keep the average read latency down to a fraction of a millisecond on the Light test. The average write latencies from the WD Black are essentially tied for first place with Samsung's drives.

The WD Black offers great 99th percentile write latency on the Light test as its SLC cache never fills. The 99th percentile read latency doesn't rank quite as high, but the full-drive score is very good.

As with the Heavy test, the only NVMe SSD we've tested that can match the WD Black's power efficiency is the Toshiba XG5. These drives get the job done much faster than a SATA drive without using any more energy.