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

  • msroadkill612 - Tuesday, October 13, 2020 - link

    Yep. I find the raw sequential speeds exciting too - its not just about IOPS :)

    This processor load balancing coincides w/ some very handy advances in mainstream system memory - typically? 64GB (2x 32GB 3200 cl16 ~$220 atm) w/ speeds to ~45-50GB/s on AM4?,

    a PCIE 4 GPU w/ a 32GB/s link vs the former 16GB/s. Its little mentioned, but seems an important plateau - ~64GB at 32GB/s seems a pretty usable supplemental tier of cache for the gpu?

    quite possibly, nvme ports on the GPU's Infinity Fabric bus on ~BigNavi to bypass a potentially bottlenecked pcie bus - AMD did it before with a pro Vega card - an nvme raid array on the gpu.

    individually they are increments in currently usable gaming memory & bandwidth (if not IOPS), but collectively they could be a force which affects gaming?

    Games are what they are due to the restrictions of yore. Of course they are coded to isolate within gpu resources.. it was the only way to run fast enough. Reduce the restrictions tho, & add new usable resources, & games change to provide new & richer experiences.

    MS FS is perhaps a forerunner of this new mindset - it likes massive memory, but is fun at 30FPS.
    Reply
  • crabperson - Tuesday, September 22, 2020 - link

    Thanks for the comparison to the PM1725a, I didn't realize how the lack of an SLC cache hurt it so much! I got a used 3.2 TB 'b version for a song, still holding out on Haswell here and probably won't upgrade until next year (Zen 3 may convince me otherwise).
    Looking forward to Phison's updated controllers and 2TB+ drives next year. Definitely don't need to waste money on the Pro line anymore.
    Reply
  • Billy Tallis - Tuesday, September 22, 2020 - link

    I was actually surprised how poorly the PM1725a fared on the consumer tests. I knew that the lack of SLC caching would hurt its writes, but it also appears to be heavily optimized for high queue depths at the expense of low queue depth performance.

    I'm planning to have some overlap between the enterprise and consumer synthetic benchmarks going forward, so there should be more opportunities to notice stuff like this.
    Reply
  • ZeDestructor - Tuesday, September 22, 2020 - link

    Any particular reson for not running the 3 desktop loads as well? I'm curious how the drives perform in more "real-world" desktop workloads too Reply
  • Billy Tallis - Tuesday, September 22, 2020 - link

    Time constraints, mostly. I grabbed the PM1725a because of its potential to show similar peak throughput, and it takes less than two hours to run the synthetic tests. A full set of ATSB results is a minimum of 12 hours plus however long it takes to fill the drive twice. Reply
  • ZeDestructor - Wednesday, September 23, 2020 - link

    Couldn't you do it during downtime and then lump the results directly into bench? I'm not particularly fussed about having the results in this particular review, but they would be very nice to have around eventually™ for weirdos like me who buy used server drives for cheap and stick em into the desktop. Reply
  • PopinFRESH007 - Tuesday, September 22, 2020 - link

    The Rocket 4 Plus was already announced and should be shipping this year with what looks to be better performance than this. Will be interesting to see what the price will be. The E18 also supports NVMe 1.4 rather than 1.3c on the 980 Pro. Reply
  • ToTTenTranz - Tuesday, September 22, 2020 - link

    So.. is this a SSD that can go into the PS5 as expandable storage? Reply
  • Billy Tallis - Tuesday, September 22, 2020 - link

    Probably. Sony hasn't put out their list of officially approved/tested SSDs yet, but this one should qualify and then some. Reply
  • UltraWide - Tuesday, September 22, 2020 - link

    The RANDOM R/W scores are average. It looks like the SK Hynix is a better SSD for real world use. Reply

Log in

Don't have an account? Sign up now