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.
Samsung's newest drives really throw down the gauntlet when it comes to idle power measurements. The mSATA-based SSDs are thriftiest of all. Sure, the 1000 GB model does use almost 50% more power at idle than the three lower capacities, but that's still less than three-tenths of a watt. Each of the smaller drives manage .21 W at active idle.
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.
Our average PCMark 7 power numbers tell a similar story, with the 1000 GB drive using significantly more power than the 120, 250, and 500 GB models. The log data shows what's happening in far greater detail. Behold!
See? The three smaller units are exceedingly similar, though with higher corresponding peak figures. The 1000 GB demonstrates significantly different characteristics, with considerably higher max use. Even when it comes off the peaks, though, it's still using more juice than the rest of the field.
As we already know, idle power is much higher comparatively, so this all makes sense. Whatever Samsung had to do to make the 1000 GB mSATA-based model possible, there's clearly something unique going on with it.
Maximum Observed Power Consumption
Triple-level cell NAND requires more power than two-bit-per-cell flash. And yet, the two top spots in this chart are dominated by Samsung's 120 GB 840 EVO in 2.5" and mSATA trim. The 1000 GB version lands mid-pack, which is still quite good for a massive flash-based repository larger than the 120, 250, and 500 GB models put together.