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

In addition to load power efficiency improvements, the 860 PRO brings modest improvements to  idle power consumption. Samsung's active idle power consumption was already pretty good, but the 860 PRO provides further savings. The idle power in slumber state is a big improvement for both of the 860 PROs, likely due to the use of LPDDR4.

Idle Wake-Up Latency

The idle wake-up latency of Samsung's drives hasn't changed, and is still hovering just above 1ms.

Mixed Read/Write Performance Conclusion
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  • Lady Fitzgerald - Tuesday, March 13, 2018 - link

    DVDs are those coaster like things that have over 600 of my movies on them. I don't plan on getting rid of them anytime soon.
  • Lady Fitzgerald - Tuesday, March 13, 2018 - link

    Wow! What did Samsung ever do to you?

    A roughly 50% decrease in idle current usage is huge if one has very many of these in use (I currently have four 4TB 850 EVOs in my desktop machine but will probably replace them with five 4TB Pros later this year), even if one doesn't factor in the reduction in heat output that will likely occur. Even when in use, the 860 Pros will draw roughly 30% less current.
  • mapesdhs - Tuesday, December 29, 2020 - link

    Hello from the future! :) I was just curious, did you indeed in the end replace those 850 EVOs with 860 Pros?

    I was hunting for info on the 860 Pro (I bagged a 256GB on ebay a year ago), found this old review. I'm upgrading my daily desktop to a 2700X just now, was wading through my SSD pile to decide on the C-drive, use the 860 Pro I hadn't done anything with yet, or move stuff around and use an 850 Pro, or maybe a Vector (my existing system has had a Vector 256GB running for 7 years. :D)

    S'funny actually looking back at what the landscape used to be before the 850 era began:

    https://www.anandtech.com/show/6363/ocz-vector-rev...

    OCZ of course took some hefty brand image flak from earlier times due to dodgy early fw releases for its older Vertex models, which is a pity because its much later Vertex4 and Vectors were rather good, indeed the older Vertex2E/3 were fine with fixed fw (I used dozens of 2Es and 3s, still do for general testing/benching).

    I buy used 840 Pro units when I can, they're very good even today. Won a fair few 850 Pro 512GB/1TB units aswell. Was particularly pleased to nab four 1TB 850 Pros from a photo company which bought them for backup, because every drive had less than 50GB written. I look at modern QLC SATA products and it baffles me why anyone would buy them, I just hunt for used 850 drives, whether EVO or Pro, or an 840 Pro (I avoid the 840 EVO due to its data retention problems which thankfully never affected the 840 Pro). Sometimes I bid on an Extreme Pro aswell, they're still good.

    I have a lot of Samsung SSDs, but over time the focus of many comments here have proven true, pricing has become kinda crazy. Moving on to NVMe, I bought a few 950 Pro, 960 Pro and 970 EVO/Plus drives (the former two mostly via the used market), but after that the competition could no longer be ignored. My more recent 1TB/2TB NVMe purchases have all been Adata XPG SX8200 Pro, just 100 UKP for the 1TB model as I write this (vs. 170 for the 970 EVO Plus, or a completely ridiculous 289 UKP for the 970 Pro). I found the Adata to be faster, which in my case involves substantial sustained sequential writes (which naturally rules out all QLC models); it's also more power efficient. The Adata is TLC of course, but then so is the 970 EVO Plus, and the former actually has a higher write endurance rating (both have 5yr warranties).

    Samsung hasn't much moved their pricing though, so I guess despite the competition they're still able to sell the products they make, but I can't figure why anyone would buy a 970 Pro when it's almost three times the cost of the Adata or other models (they really are milking the perceived MLC advantage). I know the Sabrent Rocket is very popular, but so far I've not bought one as I've been unsure of the 4K block size issue, plus I've been able to find the Adata cheaper anyway.

    I just wish the capacities would properly get a move on. Seems to me vendors are not releasing anything better because they don't have to, people are still willing to pay solid premiums for existing 2TB/4TB models. It's all a far cry from Sandisk's old promise of an 8TB SATA3 SSD way back. I guess nobody wants to rock the boat; why release an 8TB NVMe when the market is happy to splurge on 4TB and below?

    I just think it's a shame how QLC has taken over, a race to the bottom via DRAMless designs, SATA and even NVMe models that tank once their SLC emulation phase is exceeded, in some cases giving performance slower than a rust spinner. It's bizarre to think that with modern benchmark suites an old SATA like a Vector, Vertex4, 840 Pro, Neutron GTX or Extreme Pro would actually be better in some cases, heck even the Samsung 830 would probably be quicker. Modern large capacity dies are killing performance by using so few memory channels. This could easily be resolved by allowing capacities to properly increase, but they just won't do it, not yet. They'll milk the 4TB for all its worth before considering 8TB. Makes me think the margins on modern SSDs must be very high vs. models from years ago, with the former using so few ICs on the PCB. Many modern SSD PCBs contain just a controller and one flash die.

    Btw, good comment below about halving the time for a particular task being less relevant if the duration is very short in absolute terms.
  • Lady Fitzgerald - Tuesday, March 13, 2018 - link

    Again, SATA is plenty fast for data storage. NVMe is an advantage only when used for the OS and programs; even then, it isn't all that much of an advantage. If you have a task that takes ten minutes to perform and you double the speed, that's taking it down to five minutes, which is huge. If you have a task that takes 10 seconds to perform and you double the speed, that will be now be five seconds, an improvement but nowhere nearly as as noticeable. If you have a task that takes 10 milliseconds to perform and you double the speed so it now takes only 5 milliseconds, you won't notice the difference. It won't be advantageous unless you move enormous amounts of data frequently.

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