Power Management

Real-world client storage workloads leave SSDs idle most of the time, so the active power measurements presented earlier in this review only account for a small part of what determines a drive's suitability for battery-powered use. Especially under light use, the power efficiency of a SSD is determined mostly be how well it can save power when idle.

SATA SSDs are tested with SATA link power management disabled to measure their active idle power draw, and with it enabled for the deeper idle power consumption score and the idle wake-up latency test. Our testbed, like any ordinary desktop system, cannot trigger the deepest DevSleep idle state.

Idle power management for NVMe SSDs is far more complicated than for SATA SSDs. NVMe SSDs can support several different idle power states, and through the Autonomous Power State Transition (APST) feature the operating system can set a drive's policy for when to drop down to a lower power state. There is typically a tradeoff in that lower-power states take longer to enter and wake up from, so the choice about what power states to use may differ for desktop and notebooks.

We report two idle power measurements. Active idle is representative of a typical desktop, where none of the advanced PCIe link or NVMe power saving features are enabled and the drive is immediately ready to process new commands. The idle power consumption metric is measured with PCIe Active State Power Management L1.2 state enabled and NVMe APST enabled.

Active Idle Power Consumption (No LPM)Idle Power Consumption

Like most NVMe SSDs, the WD Black has a fairly high active idle power draw—the cost of keeping a PCIe 3 x4 link active. The active idle power is a bit higher than the previous WD Black SSD but is in line with drives from Samsung, Toshiba and Phison.

Enabling all the advanced PCIe and NVMe power management features doesn't have the desired effect on the WD Black SSD. The drops by almost half, but it should have dropped by at least an order of magnitude. The original WD Black SSD used aggressive power management whether or not the operating system requested it. The new WD Black seems to be unable to save much power when used on our desktop testbed, no matter what NVMe power states are requested. We will work with Western Digital to try to isolate the cause of this poor behavior. In the meantime, the WD Black is hardly the only NVMe drive where power management has problems out of the box, but Intel and Samsung have managed to produce drives that achieve very low idle power on our testbed with little or no tuning required.

Idle Wake-Up Latency

Since the WD Black is clearly unable to engage its full array of power management capabilities on our testbed, it is unsurprising to see that its wake-up latency is quite short. It is not the minimal ~15µs we usually observe from drives that aren't enabling any power savings at all, but ~230µs is still a very quick wake-up from sleep.

Mixed Read/Write Performance Conclusion
Comments Locked

69 Comments

View All Comments

  • FreckledTrout - Friday, April 6, 2018 - link

    Since they like sticking to brands they have built like "Black" maybe these should be the new VelociRaptor series? When I here these I think black its 7,200 rpm and the Raptor is 10K rpm.
  • tamalero - Friday, April 6, 2018 - link

    They should have renamed the new BLACKs as PLATINUM or TITANIUM. It works.
  • lilmoe - Thursday, April 5, 2018 - link

    Ohhh?? Not bad! Still would've preferred if they had undercut Samsung on pricing a significant bit though.
  • Samus - Thursday, April 5, 2018 - link

    nCache 3.0's design has me concerned about write thrashing, which killed many Intel SSD's suffering from a bug causing write thrashing in just a few years. The Intel 2500's were chronically plagued with this bug because many OEM's (Lenovo...) never patched them and the drives burned themselves out doing tons of unnecessary house keeping.

    Hopefully nCache 3.0 has some failsafes.
  • imaheadcase - Friday, April 6, 2018 - link

    It really blows my mind how companies are TERRIBLE at naming products. Its almost like they don't even use common sense for it. Granted these are marketed towards people who most likely are building own systems and what not...but even i'm confused with Intel branding even.

    At least name product lines based on something that stands out to people to remember.
    If i'm not mistaken, isn't Western Digital Black also a platter hardrive as well? Put that into the fact that the article says some of the old versions still be on market even if different sizes..i can easily see someone ordering wrong part.

    I miss the days when a CPU was sold based on clock speed alone.

    I guess it doesn't help that Aandtech site ventured away from consumer based stuff to more industry based news/reviews.
  • Drazick - Friday, April 6, 2018 - link

    I want this in U.2 or SATA Express format.
  • KAlmquist - Friday, April 6, 2018 - link

    At this point I wouldn't be inclined to recommend this drive. The performance reported in this review is good, but:

    1) It appears that Western Digital is only providing review samples of the 1TB model. For the smaller sizes, the only information we have about performance is the manufacturer's claims.

    2) The peculiar branding. Two names for the same drive, both of which are the same as the names of older drives. In particular, a recommendation of the Black drive is likely to result in the person getting an older, slower drive.

    3) The drive was just released so it has no track record.
  • JWKauffman - Friday, April 6, 2018 - link

    I'm curious why WD apparently isn't supplying an NVMe driver to optimize their controller. I think the question should have been raised in the review.
  • tamalero - Friday, April 6, 2018 - link

    Most third party companies do not offer any kind of driver. They rely on Windows's.

    I have a Corsair MP500, same issue.
  • JWKauffman - Friday, April 6, 2018 - link

    I understand that, but if I were WD and positioning these drives as Samsung competitors, I'd want to have a driver tailored to my controller the same as Samsung does.

Log in

Don't have an account? Sign up now