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
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  • Slash3 - Wednesday, September 23, 2020 - link

    Yeah, we may get a few early test case scenarios through an Nvidia demonstration or partner product, but any major release will probably wait to land concurrently with a full fat Directstorage update from Microsoft. I'm looking forward to it, as I've got a pretty fast storage subsystem and very few games take advantage of it even during asset loading. Reply
  • vanish1 - Tuesday, September 22, 2020 - link

    no headphone jack, no purchase. Reply
  • racerx_is_alive - Tuesday, September 22, 2020 - link

    Do we know enough about the new DirectStorage API to make a prediction about how this will perform against the 4.0 Phison controller next year? Seems like that will be a real world situation that will use lots more queues and shift performance towards the Samsung. Reply
  • KenK74 - Tuesday, September 22, 2020 - link

    This product release is a real yawner. I am keeping my 970 Pro's, and will be searching anywhere but Samsung for decent TLC's with Hardware Encryption capability when I need another. Depending on platform, software Bitlocker may not slow the drive down much, or might do so a lot. For laptops, the real problem is the extra CPU power for software encryption that exceeds differences in SSD power among the SSD drives. Yeah, hardware bitlocker has its issues, but it seems the most power efficient option for laptops that need bitlocker. Meanwhile for non-hardware encrypted drives, the SK Hynix P31 looks very good, runs with the PCI4 drives in many aspects,, and has a great price. Reply
  • PopinFRESH007 - Tuesday, September 22, 2020 - link

    Which Phision controller are you referencing? They have multiple PCIe 4.0 controllers and most of them are already available. The E16T has been available in multiple products since early in the year and the E18 is the controller for the recently announced Sabrent Rocket 4 Plus which (on paper) looks to offer better performance than the 980 Pro. The Rocket 4 Plus looks like it should also be available this year and there are a couple of other drives that are expected to launch in Q4 that will also likely be using the E18 Reply
  • dudlej84 - Tuesday, September 22, 2020 - link

    I'm confused by the conclusion claiming it regains the performance crown, but the results seem to show it beaten quite often, even by the 970 pro and 970 evo plus in some cases. What am I missing? Reply
  • XabanakFanatik - Tuesday, September 22, 2020 - link

    You're not missing anything, this is just corporate ass-wiping to reward Samsung for their terrible marketing decision to devalue the Pro brand they've been creating for a decade. Reply
  • StrangerGuy - Friday, September 25, 2020 - link

    Besides their flagship phones, I can't think of any Samsung product that aren't terrible in terms of value for money in recent years. Reply
  • alexdi - Tuesday, September 22, 2020 - link

    This is not a Pro drive. "Pro" means it maintains performance. This is a slightly faster Evo Plus and underwhelming for the price. Reply
  • PeachNCream - Tuesday, September 22, 2020 - link

    That is some trash endurance for the price. The performance numbers are okay, but not the slightest bit earth shattering. I guess in the grand scheme of things, there appears to be no really good reason for this drive to even have gone into production for as little as it brings to the table. At least it isn't QLC, but it's pretty obvious that we have reached the end of NAND and need a more durable and higher density storage medium for the solid state side of the equation. Reply

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