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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  • madmilk - Saturday, December 12, 2020 - link

    The 840 Evo is probably the worst drive Samsung has ever shipped. The first gen 2D TLC memory in the drives caused a ton of performance issues thanks to losing the charge in the flash cells leaking out rather quickly. Samsung had to push out a bunch of firmware bandaids for the issue and switched to 3D TLC for the 850 Evo. Even then, I don't think many people managed to wear them out.
  • Beaver M. - Saturday, December 12, 2020 - link

    My 840 is stored at low temperatures 5 months a year without any power source. Still works like new.
  • Spunjji - Monday, December 14, 2020 - link

    The 840 (not Pro, not Evo) would definitely take that title - it's like the Evo but without any caching or a firmware fix for the read degradation. Even with that said, I still have a couple of the absolute worst-case drives - the 840 120GB - hanging around in service as boot drives for seldom-used systems, which is a role they perform relatively well even in spite of their unique form of bit-rot. Maybe it's because Windows 10 basically rewrites the whole damn OS every 6 months? 😂
  • Oxford Guy - Monday, December 14, 2020 - link

    "which is a role they perform relatively well even in"

    Not according to HardOCP which found they had worse steady state performance than laptop hard drives.
  • Gigaplex - Wednesday, December 16, 2020 - link

    It was still better than the 840 non-Evo
  • Beaver M. - Saturday, December 12, 2020 - link

    If your case is worth anything, then the logical conclusion for SSD manufacturers should be to increase warranty and TBW massively.
    Huh. I wonder why they dont.
  • joesiv - Monday, December 14, 2020 - link

    Care to share your SMART data for one of the drives? I'm curious.
  • lmcd - Friday, December 11, 2020 - link

    While this drive is an interesting reference point, that extra $20 (or less) for a SK Hynix P31 is easily worth it.
  • Zzzoom - Friday, December 11, 2020 - link

    DWPD calculations on page 1 are wrong.
  • zepi - Saturday, December 12, 2020 - link

    This latest gen QLC with 8 channels looks too good so that it would disappear...

    In sizes from 2TB and up, it iss probably a good choice for anyone looking for a cheap drive. And thanks to SLC caching 4k random writes are crazy fast.

    One can always increase SLC cache amount by leaving 50-100G unpartitioned to make sure there is good amount of SOC cache even when filling the drive with one more Steam download.

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