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SSD Power Consumption and How It's Managed

Just how much power do SSDs use? Moving away from HDDs was nice because SSDs are quieter, lighter, better able to withstand shock and vibration, and are also more efficient. This applies to both the 2.5” and M.2 form factor, for both SATA and NVMe SSDs. However, the amount of power each draws can vary and, further, the way power states work are different. There’s also some real world differences between how desktops and laptops handle these power states.

Desktops tend to use higher power states or do not support the lowest power states, even with appropriate UEFI settings. This can cause higher overall power usage but also means the SSDs are more responsive. Laptops, on the other hand, are designed to be efficient and tend to support the full power capabilities of storage. For SATA SSDs this means Aggressive Link Power Management (APLM) and DevSleep/DevSlp. For NVMe SSDs this means an array of five or more power states with varying latencies, from full power to maximum idle, as a subset of the NVMe specification. This includes the OS’s Autonomous Power State Transition and PCIe’s Active State Power Management features.

Overview of NVMe power management. Source: NVM Express.

2.5” SATA drives use 5V while the M.2 specification calls for 3.3V. In practice, the former will not exceed about 1.5A, or 7.5W, while the latter is designed for 2A but often peaks at about 3A, or up to 10W, with the voltage having a tolerance of ±5%. SSDs should idle in the 20-100mW range on a desktop with power management, or as low as ~5mW on a laptop. Drives will be rated for average read and write power consumption with usually write being higher in practice for NVMe due to performance asymmetry. A SATA SSD will usually be below 4W maximum power consumption, with lower-end NVMe usually around 3.5W and higher-end up to 8.5W or more.

DEVSLP

SATA power states. Image courtesy Phison. See APLM on Wikipedia for basic details.

It’s difficult to measure and gauge power usage without expensive hardware. It’s also challenging to compare different drives due to changing conditions, such as battery wear. Most important, though, is the platform - desktop or laptop - and the type of usage, or workload. Consumers tend to mostly stay in lower power states with sudden bursts of activity. Given the relatively low power capabilities of modern SSDs, the difference in laptop battery life is generally pretty small as a result.

NVMe power and PCIe link states. Source: NVM Express, as above.

We offera range of SSDs with different power consumption ranges. Drives that use DRAM-less controllers and fewer channels will use less power. Drives at higher capacities tend to use more power. Drives with newer flash, which includes our Rocket 4 Plus, tend to pull a bit less power in comparison. All of our NVMe drives support multiple power states with an effort to improve power efficiency without reducing responsiveness.