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

Idle power usage seems to have taken a step backward from the Crucial MX300 to the Crucial MX500. Both the active idle and the slumber power state consumption are higher than most mainstream SATA SSDs, but it isn't one of the extreme outliers that has broken power management.

Idle Wake-Up Latency

The idle wake-up time for the Crucial MX500 of about 1ms is higher than many mainstream drives, but is a big improvement over the 3.3ms of the Crucial MX300. The Marvell-based drives from Western Digital/SanDisk seem to offer the best combination of low power consumption and quick wake-ups.

Mixed Read/Write Performance Conclusion


View All Comments

  • mapesdhs - Saturday, December 23, 2017 - link

    Forgot to mention, the Vertex 4 is still a good drive. Just make sure the fw is up to date. Think the latest is 1.5. Reply
  • peevee - Tuesday, December 19, 2017 - link

    "SMI controllers tend to be more popular for budget products"... "Silicon Motion has been working to improve their controllers and move toward the high end, but the MX500 isn't even adopting the newer SM2259"... "but they're not as large or numerous as on previous MX series drives"

    race to the bottom.
  • MajGenRelativity - Tuesday, December 19, 2017 - link

    Did you look at the improved performance numbers? I'm not sure how that supports a race to the bottom Reply
  • Wolfpup - Tuesday, December 19, 2017 - link

    Ugh, is EVERYONE using TLC now? I was uncomfortable enough with MLC.

    I'm not crazy about switching away from Marvell either...though I suppose as long as it works and the software Micron writes is good...

    I really want a higher end MLC (or SLC!) drive from Crucial/Micron.

    My main system is still using a 2012 Crucial drive though. It literally launches programs in maybe 1-2 seconds MAX, so who the heck cares if it were 42x faster? (Literally the only time I've ever see it take any actual time to respond to anything was when I was doing something else while running TRIM on it for no real reason.)

    But my next drive I'd like to be MLC Crucial/Micron too...
  • MajGenRelativity - Tuesday, December 19, 2017 - link

    BX300 is your best bet Reply
  • smilingcrow - Tuesday, December 19, 2017 - link

    Don't waste your time with SLC but look at Optane. Reply
  • MajGenRelativity - Tuesday, December 19, 2017 - link

    That's another alternative Reply
  • valinor89 - Tuesday, December 19, 2017 - link

    Optane is a first gen product... I think I will pass this round and watch for the next generations .

    Also, Optane is not in the same price range as "conventional" SSD.
  • extide - Wednesday, December 20, 2017 - link

    It's a bit higher but not outrageous by any means. It's FAR cheaper than several of the early SSD's I bought in terms of $/GB. Frankly for its performance, I think it's priced pretty aggressively, TBH. Reply
  • DanNeely - Tuesday, December 19, 2017 - link

    SLC is dead in anything except very non-mainstream products (eg low capacity embedded flash built on a process so large that even doing ECC is optional), at only 1/3 the density of TLC per chip it's nowhere near cost competitive. The same factor is killing off MLC as 3d TLC improves. I suspect over the next year or three MLC flash will gradually fade away too.

    If they can get the total write count up high enough, QLC will start displacing TLC over the next few years. That number was only a few dozen writes a few years ago; I haven't seen any updates since then. OTOH over similar timespans TLC write endurance has climbed from a few hundred writes to a few thousand; if QLC has been able to improve equally we might start seeing it soon in entry level products.

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