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 Wake-Up Latency

The Optane SSD 800p has a bit of an unusual suite of power management capabilities. Previous Optane products have not implemented any low-power sleep states, giving them quite high idle power consumption but entirely avoiding the problem of latency waking up from a sleep state. The 800p implements a single low-power sleep state, while most NVMe SSDs that have multiple power states have at least two or three idle states with progressively lower power consumption in exchange for higher latency to enter or leave the sleep state. On the other hand, the 800p has three tiers of active power levels, so devices with strict power or thermal limits can constrain the 800p when properly configured.

Unfortunately, our usual idle power testing method didn't work with the 800p, leading it to show only a modest reduction in power rather than a reduction of multiple orders of magnitude. This may be related to the fact that the Optane SSD 800p indicates that it may take over a full second to enter its idle state. This is an unusually high entry latency, and something in our system configuration is likely preventing the 800p from fully transitioning to idle. We will continue to investigate this issue. However, based on the specifications alone, it looks like the 800p could benefit from an intermediate idle state that can be accessed more quickly.

(I should mention here that the last Intel consumer SSD we reviewed, the 760p, also initially showed poor power management on our test. We were eventually able to track this down to an artifact of our test procedure, and determined that the 760p's power management was unlikely to malfunction during real-world usage. The 760p now ranks as the NVMe SSD with the lowest idle power we've measured.)

Mixed Read/Write Performance Conclusion
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  • beginner99 - Friday, March 9, 2018 - link

    Exactly. Anything below 240GB is not a workable solution nowadays. I remember my first intel g2 80GB. constant micro-managing where to put files and which app gets to be on the ssd and which not. Or for my parents I back then got them a 64 gb drive. When the win 10 update came it was not possible to update because updating windows 7 to 10 requires more than 64gb. Reply
  • Calin - Friday, March 9, 2018 - link

    I do use a 120GB SSD on my desktop, and it works good enough with a 2TB hard drive. I even use a 90% partition, as early SSDs had performance problems when close to full. Reply
  • sharath.naik - Thursday, March 8, 2018 - link

    was rapid mode tried on Samsung drives?. not sure with a large enough ram the difference in random performance would matter that much. Reply
  • Billy Tallis - Thursday, March 8, 2018 - link

    Half the test suite is run on Linux, so Rapid Mode isn't an option. And in general, I don't approve of third-party software that second-guesses the decisions made by core parts of the OS like the virtual memory system—especially not when those tools put user data at risk without being absolutely clear about what they're really doing. Reply
  • eddieobscurant - Friday, March 9, 2018 - link

    Billy , do you have any news on micron's QuantX ? Reply
  • Dragonstongue - Thursday, March 8, 2018 - link

    Intel and Micron (IM) joint venture, Intel "branded" as Optane either way is 3D XPoint..far as I understood Micron decided to "drop it" so is Intel going about it all on their own, was Unity Semiconductors who was bought out by Rambus 2012, that likely not a good thing either (they) RB seem more prevalent to sue people vs making a tangible product everyone wants (IMO)

    the above 3d x, optane whatever seems like another thing that "on paper" seems like would be a decent thing, but, the price factor puts it into a "there are better options available" that offer similar performance or at the very least substantially better $/gb value.

    I think that is what Micron was seeing, no real way to get the "value" out of it without charging too high a price to make it market worthwhile for them and consumer, Intel is their own fish and they always (again IMO) charge substantial price for a "do we really need this" type product (like Nvidia) cut corners or cut down performance that could have been, but still want top dollar, and "next year" come out with a more full fat version (that should have been the previous year) and want more $ for the "upgrade" planned obsolescence/upgrade path.

    for a loose example, Samsung 950 EVO M.2 250gb (pro faster but ofc more pricey)
    I see available for ~$160 CAD
    read/write 3200/1900
    QD1 Thread
    Random Read: 14,000 IOPS
    Random Write: 50,000 IOPS
    QD32 Thread
    Random Read: 380,000 IOPS
    Random Write: 360,000 IOPS

    their "power draw" and latency do not seem to be praiseworth either, so it still leads me to the same question "why bother"...also, I really wish M.2 drives were maybe a toned down speed version so it could be "less expensive" here I thought that by going smaller and smaller node and going from SLC to MLC to 3d etc price would drop and drop while performance would go up and up, seems that the only real thing that has changed is the less on the "board" the further they crank the speed give smaller capacity and increase the price *facepalm*
    Reply
  • Lolimaster - Friday, March 9, 2018 - link

    10x less latency
    15x faster in QD1r
    4X faster in QD1w
    Reply
  • Adramtech - Saturday, March 10, 2018 - link

    Micron has no plans to drop QuantX and are providing an update at their May tech conference. Reply
  • shabby - Thursday, March 8, 2018 - link

    Leave it to intel to artificially cripple a product on purpose, who does this? Reply
  • boeush - Thursday, March 8, 2018 - link

    Seems to me, if you really want supper-fast, low-latency high-endurance random read/write at low QD and capacities ~128GB for a lot of $$$, then just get a bunch of RAM and a UPS (to prevent data loss in case of power failure.). No SSD technology will ever beat good ol' RAM in terms of performance. In this case, for mass storage you just need fast sequential reads and writes so you can quickly map your filesystem to/from RAM on system startup/shutdown, respectively...

    In light of which, until Intel comes out with their next-gen Optane at 512 GB+ capacities in M.2 package, the current product feels like a solution on search of a problem
    Reply

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