The Crucial MX500 1TB SSD Review: Breaking The SATA Moldby Billy Tallis on December 19, 2017 8:00 AM EST
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.
Idle power usage seems to have taken a step backward from the Crucial MX300 to the Crucial MX500. Both the active idle and the slumber power state consumption are higher than most mainstream SATA SSDs, but it isn't one of the extreme outliers that has broken power management.
The idle wake-up time for the Crucial MX500 of about 1ms is higher than many mainstream drives, but is a big improvement over the 3.3ms of the Crucial MX300. The Marvell-based drives from Western Digital/SanDisk seem to offer the best combination of low power consumption and quick wake-ups.