Power Management Features

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.

For many NVMe SSDs, the closely related matter of thermal management can also be important. M.2 SSDs can concentrate a lot of power in a very small space. They may also be used in locations with high ambient temperatures and poor cooling, such as tucked under a GPU on a desktop motherboard, or in a poorly-ventilated notebook.

Intel SSD 660p 1TB
NVMe Power and Thermal Management Features
Controller Silicon Motion SM2263
Firmware NHF034C
Feature Status
1.0 Number of operational (active) power states 3
1.1 Number of non-operational (idle) power states 2
Autonomous Power State Transition (APST) Supported
1.2 Warning Temperature 77°C
Critical Temperature 80°C
1.3 Host Controlled Thermal Management Supported
 Non-Operational Power State Permissive Mode Not Supported

The Intel SSD 660p's power and thermal management feature set is typical for current-generation NVMe SSDs. The rated exit latency from the deepest idle power state is quite a bit faster than what we have measured in practice from this generation of Silicon Motion controllers, but otherwise the drive's claims about its idle states seem realistic.

Intel SSD 660p 1TB
NVMe Power States
Controller Silicon Motion SM2263
Firmware NHF034C
Active/Idle Entry
PS 0 4.0 W Active - -
PS 1 3.0 W Active - -
PS 2 2.2 W Active - -
PS 3 30 mW Idle 5 ms 5 ms
PS 4 4 mW Idle 5 ms 9 ms

Note that the above tables reflect only the information provided by the drive to the OS. The power and latency numbers are often very conservative estimates, but they are what the OS uses to determine which idle states to use and how long to wait before dropping to a deeper idle state.

Idle Power Measurement

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 if supported.

Active Idle Power Consumption (No LPM)Idle Power Consumption

The Intel 660p has a slightly lower active idle power draw than the SM2262-based drives we've tested, thanks to the smaller controller and reduced DRAM capacity. It isn't the lowest active idle power we've measured from a NVMe SSD, but it is definitely better than most high-end NVMe drives. In the deepest idle state our desktop testbed can use, we measure an excellent 10mW draw.

Idle Wake-Up Latency

The Intel 660p's idle wake-up time of about 55ms is typical for Silicon Motion's current generation of controllers and much better than their first-generation NVMe controller as used in the Intel SSD 600p. The Phison E12 can wake up in under 2ms from a sleep state of about 52mW, but otherwise the NVMe SSDs that wake up quickly were saving far less power than the 660p's deep idle.

Mixed Read/Write Performance Conclusion


View All Comments

  • mapesdhs - Wednesday, August 8, 2018 - link

    Please explain the Vertex2, because I have a lot of them and so far none have failed. Or do you mean the original Vertex2 rather than the Vertex2E which very quickly replaced it? Most of mine are V2Es, it was actually quite rare to come across a normal V2, they were replaced in the channel very quickly. The V2E is an excellent SSD, especially for any OS that doesn't support TRIM, such as WinXP or IRIX. Also, most of the talk about the 840 line was of the 840 EVO, not the standard 840; it's hard to find equivalent coverage of the 840, most sites focused on the EVO instead. Reply
  • Valantar - Wednesday, August 8, 2018 - link

    If the Vertex2 was the one that caused BSODs and was recalled, then at least I had one. Didn't find out that the drive was the defective part or that it had been recalled until quite a lot later, but at least I got my money back (which then paid for a very nice 840 Pro, so it turned out well in the end XD). Reply
  • Oxford Guy - Friday, August 10, 2018 - link

    Not recalled. There was a program where people could ask OCZ for replacements. But, OCZ also "ran out" of stock for that replacement program and never even covered the drive that was most severely affected: the 240 GB 64-bit NAND unit. Reply
  • BurntMyBacon - Wednesday, August 8, 2018 - link

    I believe the problems that plagued the 840 EVO were relevant to the 840 based on two facts. Both SSDs used the same flash. Samsung eventually released a (partial) fix for the 840 similar to the 840 EVO. The fix was apparently incompatible with Linux/BSD, though. Reply
  • Spunjji - Wednesday, August 8, 2018 - link

    You'd also be providing useless data by doing so. The drives will have been superseded at least twice before you even have anything to show from the (very expensive) testing. Reply
  • JoeyJoJo123 - Tuesday, August 7, 2018 - link

    >muh ssd endurance boogeyman
    Like clockwork.
  • StrangerGuy - Tuesday, August 7, 2018 - link

    "I am a TRUE PROFESSIONAL who can't pay more endurance for my EXTREME SSD WORKLOADS by either from my employer or by myself, I'm the poor 0.01% who is being oppressed by QLC!" Reply
  • Oxford Guy - Tuesday, August 7, 2018 - link

    Memes didn't make the IBM Deathstar drives fun and games. Reply
  • StrangerGuy - Tuesday, August 7, 2018 - link

    I'm sure you were the true prophetic one warning us about those crappy those 75GXPs before they were released, oh wait.

    I'm sorry why are you here and why should anyone listen to you again?
  • Oxford Guy - Tuesday, August 7, 2018 - link

    Memes and trolling may be entertaining but this isn't really the place for it. Reply

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