Results: Power Consumption
Idle Power Consumption
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, a part of the SATA 3.2 host specification. And although DevSleep requires a capable SSD and a compatible platform, enabling it takes power consumption down to a tiny figure. This is why we test active idle; it's easy to identify, and is still where SSDs spend most of their time.
The X210 fares well in this metric partly as a result of its Marvell 88SS9187 controller. Registering 0.47 W, both SSD valiantly charge at the most power-friendly drives in our comparison, even if they fall a bit short. But given the environments these SSDs will drop into, one-tenth of a watt isn't going to make or break the efficiency measurement of an entry-level server or high-end laptop.
PCMark 7 Average Power Consumption
If we log power consumption through a workload, even a relatively heavy one, we see that average draw 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.
Averaged out over a complete PCMark 7 run, the 512 GB X210 uses 0.9 W, while the 256 GB model settles in at 0.85 W. That puts SanDisk's drives around the same level as Samsung's 840 EVOs and OCZ's more recent offerings.
Let's plot the log data for more detail:
The distances between peaks comes down to writing used LBA spaces. Basically, PCMark 7 is formatting the addresses the component traces will use, which takes longer on the 512 GB X210 than on the 256 GB version. That's why the smaller drive gets started first.
As far as power consumption goes, there really isn't much variance between the two. Both hit the same idle floor and demonstrate similar peak figures. The higher-capacity SSD simply uses a little more power.
Maximum Observed Power Consumption
Unfortunately, that's enough to put the X210s toward the bottom of the chart in maximum observed power consumption. These drives could use more power in certain workloads or under specific conditions, but this is the highest we saw in our own test suite.