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

The active idle power consumption of the Crucial BX300 is the same as for the BX200. Both are a bit on the high side, but there are Silicon Motion drives with both higher and lower active idle draws. With SATA link power management enabled, the BX300's idle power draw is better than average, but 20mW worse than what the BX200 and Intel 545s manage with older and newer Silicon Motion controllers.

Idle Wake-Up Latency

The BX200 had a serious problem with idle wake-up latency of over 10ms, which the BX300 has fixed. The BX300 wakes up quickly, though the drives with the Phison S10 controller are still the quickest by far.

Mixed Read/Write Performance Conclusion
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  • MrSpadge - Tuesday, August 29, 2017 - link

    A budget drive with budget price, without any real weakness - well done!
  • nwarawa - Tuesday, August 29, 2017 - link

    Does this thing still have partial power loss protection? I don't see much in the way of capacitors in the images, at least compared to the M500 up to the MX300
  • Ryan Smith - Wednesday, August 30, 2017 - link

    No, it does not. The BX series always omits that feature.
  • nwarawa - Wednesday, August 30, 2017 - link

    "The BX series always omits that feature."

    Incorrect. The BX100 most definitely did. I even confirmed with Crucial themselves.
  • Samus - Sunday, September 3, 2017 - link

    BX100 PCB: http://www.storagereview.com/images/StorageReview-...

    No power loss protection.

    BX series has never offered it. If Micron/Crucial said otherwise, they lied.
  • Samus - Sunday, September 3, 2017 - link

    Here is a high-res shot from AT: http://images.anandtech.com/doci/9144/IMG_2266.jpg

    Kristian seems to believe in that review there are enough caps to drive 8 NAND dies, a piece of 1.35v DDR3 DRAM, and the SMI controller, for 200us.

    As an engineer, without even measuring the capacitance of the tiny inlays of that PCB, it's visually clear this is physically impossible. Just comparing to the PCB of the MX100 which has a dedicated PLP circuit and rows of caps, no matter how much power efficiency the BX100 design has over the MX100, the level of PLP is going to be entirely different, which leads me to this thread:

    This thread has a good definition of "power loss protection" on the BX100: http://forums.crucial.com/t5/Crucial-SSDs/Crucial-...

    Basically, it's discussed that about 2-4MB of the indirection table cache (which is write-thru to the NAND by design) can be protected by the design. In other words, insignificant and irrelevant. This is why PLP was never marketed for the BX100. It's useless. Most non-enterprise implementations are.
  • nwarawa - Tuesday, September 12, 2017 - link

    I wouldn't call partial PLP "useless". Old SSDs wouldn't just lose SOME data. They would often lose ALL data. It would be nice to see an updated version of this test from years ago:

    http://lkcl.net/reports/ssd_analysis.html

    The M4 didn't have the partial PLP, so it would be interesting to see how much of an improvement the M500 with it's partial PLP made. For that matter, some Phison S10 drives and Samsung's last few years of models mention some form of firmware based PLP... so how effective are they?

    Anyone want to start a GoFundMe for this guy to run some updated tests?
  • nwarawa - Tuesday, September 12, 2017 - link

    Update: I reached out to lkcl to see if he's interested in continuing the testing, and if GoFundMe would work for him. I said I would chip in $10-$20 to see some updated test results. Anyone else interested in these tests?
  • nwarawa - Tuesday, September 12, 2017 - link

    Samus, you didn't read carefully enough. It's not whether or not it has FULL power loss protection, but PARTIAL power loss protection. You can read anandtech's review of the BX100 for more information on what that entails. The very link you posted shows the little capacitors that are sufficient for the PARTIAL power loss protection. The reason this was even brought up is that there seem to be fewer of those capacitors on the BX300, which raised doubt as to if the feature was still included. I was just in a convo with Crucial directly, and they confirmed that the BX300 does indeed still have partial PLP.
  • FunBunny2 - Tuesday, August 29, 2017 - link

    when 3D NAND was first proposed, durability was supposed to improve because such devices could/would be built on larger nm nodes. has that actually happened? what node(s) are being used for 32/64L?

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