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.

Samsung 980 PRO
NVMe Power and Thermal Management Features
Controller Samsung Elpis
Firmware 1B2QGXA7
NVMe
Version
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 82°C
Critical Temperature 85°C
1.3 Host Controlled Thermal Management Supported
 Non-Operational Power State Permissive Mode Not Supported

The set of power management features supported by the 980 PRO is the same as what the 970 generation offered. The active state power levels have been tweaked and the highest power state can now reach 8.49W: definitely high for a M.2 drive, but not as problematic as the 10.73W declared by the Phison E16-based Seagate FireCuda 520. Power state transition latencies for the 980 PRO have also been adjusted slightly, but the overall picture is still a promise of very quick state changes.

Samsung 980 PRO
NVMe Power States
Controller Samsung Elpis
Firmware 1B2QGXA7
Power
State
Maximum
Power
Active/Idle Entry
Latency
Exit
Latency
PS 0 8.49 W Active - -
PS 1 4.48 W Active - 0.2 ms
PS 2 3.18 W Active - 1.0 ms
PS 3 40 mW Idle 2.0 ms 1.2 ms
PS 4 5 mW Idle 0.5 ms 9.5 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, and depending on which NVMe driver is in use. Additionally, there are multiple degrees of PCIe link power savings possible through Active State Power Management (APSM).

We report three idle power measurements. Active idle is representative of a typical desktop, where none of the advanced PCIe link power saving features are enabled and the drive is immediately ready to process new commands. Our Desktop Idle number represents what can usually be expected from a desktop system that is configured to enable SATA link power management, PCIe ASPM and NVMe APST, but where the lowest PCIe L1.2 link power states are not available. The Laptop Idle number represents the maximum power savings possible with all the NVMe and PCIe power management features in use—usually the default for a battery-powered system but rarely achievable on a desktop even after changing BIOS and OS settings. Since we don't have a way to enable SATA DevSleep on any of our testbeds, SATA drives are omitted from the Laptop Idle charts.

 

We haven't sorted out all the power management quirks (or, less politely: bugs) on our new Ryzen testbed, so the idle power results below are mostly from our Coffee Lake system. The PCIe Gen4 drives have been tested on both systems, but for now we are unable to use the lowest-power idle states on the Ryzen system.

Since AMD has not enabled PCIe 4 on their Renoir mobile platform and Intel's Tiger Lake isn't quite shipping yet, these scores are still fairly representative of how these Gen4-capable drives handle power management in a typical mobile setting. Once we're able to get PCIe power management fully working crash-free on our Ryzen testbed, we'll update these scores in our Bench database.

Idle Power Consumption - No PMIdle Power Consumption - DesktopIdle Power Consumption - Laptop

The active idle power draw from the 980 PRO unsurprisingly differs quite a bit depending on whether it's running the PCIe link at Gen3 or Gen4 speeds. At Gen3 speeds, the active idle power is decently low for an 8-channel controller and is an improvement over the 970 generation. At Gen4 speeds the active idle power is a bit on the high side of normal, but still lower than the Phison E16 and the WD Black that is something of an outlier.

The desktop idle power draw for the 980 PROs is less than half what we saw with the Samsung 970 generation drives, but not quite as low as the Silicon Motion SM2262EN achieves. On our Coffee Lake system, the 980 PROs are both able to achieve single digit milliwatt idle power.

Idle Wake-Up Latency

The idle wake-up times for the 980 PROs are all very quick, though waking up from the desktop idle state to Gen4 speed does seem to take longer than reestablishing a Gen3 link. Some of the previous-generation Samsung drives we tested exhibited wake-up latencies of several milliseconds, but so far the 980 PRO doesn't seem to do that and aggressively using the deepest idle states achievable won't noticeably hurt system responsiveness.

Mixed Read/Write Performance Conclusion: Top Shelf, No Drama
POST A COMMENT

137 Comments

View All Comments

  • Tomatotech - Wednesday, September 23, 2020 - link

    Updating my comment - StorageReview tested the 980 Pro with enterprise workloads. It seems a fantastic performer there, with some of the highest numbers I’ve ever seen, especially in random 4K r/w, which is an area I’ve long felt nvme was neglecting. The 980 Pro is a drive that finally performs well in this area.

    That said, that performance requires a monster 128 queue depth which is fine in enterprise but is very rarely seen in desktop computing. Oh well, it’s called Pro for a reason. That aspect of its performance justifies the price in my view.

    https://www.storagereview.com/review/samsung-980-p...
    Reply
  • Someguyperson - Tuesday, September 22, 2020 - link

    Why haven't you tested any Phison E16 drives yet? I get that power consumption was seen as an issue, but with these drives pulling 20 watts, I don't think Phison E16 drives would be all that different. That said, the only way to validate any of those claims is by actually testing the drives. Which you haven't done yet. Reply
  • Slash3 - Tuesday, September 22, 2020 - link

    The Firecuda 520 is a Phison E16 design. Reply
  • londedoganet - Tuesday, September 22, 2020 - link

    > Samsung Elpis

    ouk élabon pólin; álla gàr elpìs éphē kaká
    Reply
  • pogostick - Friday, October 2, 2020 - link

    I have no idea what this says, but I know exactly what it says. Reply
  • Duncan Macdonald - Tuesday, September 22, 2020 - link

    An extreme endurance drive (all SLC) would seem to be a useful niche product for some users. It should be possible to produce such a drive with just a software modification to the controller. Obviously the cost/GB would be much higher but for some uses the extra cost would be worth it.
    (The same amount of NAND that would provide 2TB in TLC mode would only provide around 600GB in SLC mode.)
    Reply
  • Tomatotech - Tuesday, September 22, 2020 - link

    You’re talking about enterprise SSDs. They’re over that way. And one was included in the testing in this very article you’re reading. Reply
  • FunBunny2 - Wednesday, September 23, 2020 - link

    "(The same amount of NAND that would provide 2TB in TLC mode would only provide around 600GB in SLC mode.)"

    if memory serves, at least one of the AT SSD reviewers has pointed out that TLC/QLC NAND run in 'SLC mode' isn't actually SLC. and doesn't perform like it.
    Reply
  • CheapSushi - Thursday, December 17, 2020 - link

    Get OPTANE. Why do so many people constantly overlook Optane? Optane has even higher endurance than SLC. Reply
  • lilmoe - Tuesday, September 22, 2020 - link

    With the move to 128l 8nm NAND, I was hoping for MLC with higher capacity, faster performance and lower prices at the same endurance level of the 970 Pro.

    But with TLC, this is still significantly more expensive than the EVO Plus, and not worth it for the average consumer considering the competition. It's just making Hynix Gold look that much better. This isn't what the Pro series customers wanted, Samsung...

    Oh well, RIP Pro line... Really disappointed.
    Reply

Log in

Don't have an account? Sign up now