Results: Power Consumption
Idle Power Consumption
Idle consumption is the most important power metric for consumer and client SSDs. After all, solid-state drives complete host commands quickly, and then drop back down to idle. Aside from the occasional background garbage collection, a modern SSD spends most of its life doing very little. Enterprise-oriented drives are more frequently used at full tilt, making their idle power numbers less relevant. But this just isn't the case on the desktop, where the demands of client and consumer computing leave most SSDs sitting on their hands for long stretches of time.
Active idle power numbers are critical, especially when it comes to their impact on mobile platforms. Idle means different things on different systems, though. Pretty much every drive we're testing is capable of one or more low-power states, up to and including DevSleep. That last feature is a part of the SATA 3.2 host specification. And while it requires a capable SSD and a compatible platform, enabling it takes power consumption down to a very small number.
Marvell's 88SS9189 features enhanced power management (at least, that's what Crucial tells us). The improvements don't only affect active idle consumption, either. Partial hibernation and DevSlp are also more efficient. Desktop users aren't going to care much, but given the M500's mediocre power numbers, Crucial needed better performance in this metric to make the M550 a more attractive mobile option.
The M550 does represent forward progress, but it still can't hold a candle to Samsung's efforts. This is the first benchmark where the 840 EVO scores a meaningful victory over the M550.
Take everything that was beautiful about Crucial's M500, add more capacity, and then more performance. The M550 sets its predecessor's shortcomings right. Excessive redundancy and conservative engineering resulted in the M500's modest performance. A year later, the M550 sports an updated controller and firmware, putting it in elite company.
The 512 GB M550 is as quick as the 1024 GB model, but sells for $200 less, making it more palatable to mainstream audiences.
PCMark 7 Average Power Consumption
If we log power consumption through a workload, even a relatively heavy one, we see that average use is still pretty close to the idle numbers. Maximum power may spike fiercely, but the usage seen during a PCMark 7 run is pretty light. You can see the drives fall back down to the idle "floor" between peaks of varying intensity.
If I knew nothing else about the M550s and was shown this chart, I'd assume that the drives are very fast. There's no real drama to report on; reads and writes are handled quickly before power drops back into the idle range. The spikes don't last long, and the initial few minutes of the benchmark, which sometimes reveal awkward power use, are instead quite clean.
Average power consumption across PCMark 7 represents an improvement over Crucial's 480 and 960 GB M500s. But higher-than-average active idle still hurts the new M550s a bit.
Maximum Observed Power Consumption
Higher-capacity drives use more power under heavy loads. No surprise there.
