Mixed IO Performance

Our tests of mixed read/write IO vary the workload from pure reads to pure writes at 10% increments. Each mix is tested for up to 1 minute or 32GB of data transferred. The mixed random IO test uses a queue depth of 4 while the mixed sequential IO test uses a queue depth of 1. The tests are confined to a 64GB span of the drive, and the drive is given up to one minute of idle time in between each mix tested.

Mixed IO Performance
Mixed Random IO Mixed Sequential IO

The QLC NVMe drives like the Corsair MP400 have a clear advantage over the DRAMless TLC drives for mixed read/write workloads. This is particularly pronounced for the mixed random IO test, where the DRAMless TLC drives are even slower than the QLC SATA drive. On the mixed sequential IO test, those DRAMless TLC drives can compete with some of the slower QLC NVMe drives, but the 8-channel Phison E12 controller used in the Corsair MP400 and Sabrent Rocket Q helps them stay ahead as the faster budget NVMe strategy.

Mixed IO Efficiency
Mixed Random IO Mixed Sequential IO

The budget NVMe drives all have worse power efficiency during the mixed IO tests than any of the high-end options, but the Corsair MP400 has some of the best efficiency scores within the budget NVMe segment. The 8TB Sabrent Rocket Q trails behind the 1TB MP400 because of the extra power draw of so many NAND dies.

Mixed Random IO
Mixed Sequential IO

The Corsair MP400's performance curves through the mixed random and sequential IO tests generally resemble what we saw for the Sabrent Rocket Q. On the mixed sequential IO test, the 8TB Rocket Q generally maintained a clear performance lead over the 1TB MP400 (at the cost of much higher power draw), but their performance scaling across the random IO test is very similar. The overall shape of the performance curves for these QLC drives has a lot more in common with mainstream TLC drives than it does with the entry-level DRAMless TLC drives; the QLC drives are slower than mainstream TLC drives, but not as obviously limited as the DRAMless drives.

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 or NVMe 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.

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

Idle Wake-Up Latency

The Corsair MP400 identifies itself as having the same idle power management capabilities as the Sabrent Rocket Q, and significantly lower maximum power draw in its active power states than the very pessimistic figures our 8TB Rocket Q sample provides to the OS.

The active and desktop idle power values we measured for the MP400 are a bit lower than for the Rocket Q 8TB, which is to be expected given the lower part count on the 1TB MP400. Waking up from the intermediate desktop idle state is extremely quick, but waking from the deepest sleep state is just a bit on the slow side.

Synthetic Benchmarks Conclusion: Entry Level QLC
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  • Spunjji - Monday, December 14, 2020 - link

    That's a good point. Locking off 50GB a 2TB drive's capacity isn't a huge penalty to pay for the reward of having a guaranteed ~12.5GB of SLC cache available at all times, even with a "full" drive.
  • kavanoz - Saturday, December 12, 2020 - link

    When will Anandtech review Western Digital Black SN850?
  • Samus - Sunday, December 13, 2020 - link

    If you are getting a 1TB PCIe 3.0 SSD it'd be ridiculous not to get the P31, I replaced my WD SN750 that was chronically overheating and throttling in my system (65C-70C!) and the Hynix barely cracks 50C AND its faster. $110 shipped on Amazon.
  • Oxford Guy - Monday, December 14, 2020 - link

    Remember... if the drive doesn't fail spectacularly then it just has to be good quality.

    Speaking of "tropes"...

    Paying more than one should for inferior technology is not a problem at all. As long as the drive doesn't kick the bucket then it's all good.
  • Snowleopard3000 - Thursday, December 17, 2020 - link

    Does anyone know where to get 15x15x2mm Soft Silicone Thermal Conductive Pads for the M.2 drives, I am specifically looking for 2mm thick ones.

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