The Crucial MX500 500GB SSD Review: A Second Lookby Billy Tallis on February 2, 2018 9:30 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.
With less DRAM, the 500GB Crucial MX500 saves a bit of power relative to the 1TB model when the drives are in low power state, but their active idle power consumption is essentially the same. In both scores, the Crucial MX500 is worse than many competitors and the predecessor MX300.
The Crucial MX500 is reasonably quick to wake from idle, though the BX300 and the ADATA SU800 are substantially faster to wake up with the same SSD controller. The MX300 had been unusually slow to wake.