The ADATA XPG SX6000 Pro 1TB SSD Review: Realtek's Entry-level NVMe Solution

Power Management Features

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.

For many NVMe SSDs, the closely related matter of thermal management can also be important. M.2 SSDs can concentrate a lot of power in a very small space. They may also be used in locations with high ambient temperatures and poor cooling, such as tucked under a GPU on a desktop motherboard, or in a poorly-ventilated notebook.

The ADATA SX6000 Pro declares comically high warning and critical temperature thresholds which we don't believe for a minute, but we are inclined to believe that thermal throttling is a pretty remote possibility for this drive. It doesn't implement either of the relevant NVMe 1.3 power and thermal management features, but only one of those two is commonly found on competing drives.

The SX6000 Pro's firmware claims to have two idle power states that are both very low power, with reasonably fast transition times. This doesn't match up with ADATA's published spec sheet, which only claims that the drive can get down to about 140mW at idle.

Note that the above tables reflect only the information provided by the drive to the OS. The power and latency numbers are often very conservative estimates, but they are what the OS uses to determine which idle states to use and how long to wait before dropping to a deeper idle state.

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.

Note: Earlier this year we upgraded our power measurement equipment and switched to measuring idle power on our Coffee Lake desktop, our first SSD testbed to have fully-functional PCIe power management. The below measurements are all new, and are not a perfect match for the older measurements in our previous reviews and the Bench database.

ADATA's spec sheet proves to be more accurate than the drive's own firmware when it comes to idle power draw; the controller's deepest sleep states don't really work, and the lowest power levels we observed from the SX6000 Pro are more in line with pre-DEVSLP SATA drives. We really aren't surprised to see Realtek stumble here since literally everyone else in the industry has had trouble with this at one time or another. This is nowhere near the worst case of broken SSD power management we've seen. We wouldn't really recommend the SX6000 Pro for mobile use, but its power management should be fine to keep idle temperatures low during desktop use.

Since the SX6000 Pro doesn't actually get into any particularly deep sleep states, it's nice to see that it has extremely fast wake-up times; there's basically no downside to using the power management capabilities this drive does have working.