Although it's often true that enterprise-class drives are subjected to 24x7 workloads, that's not always the case. When these SSDs are idling, they're all using less than 1 W.
Although Micron's P400e delivers very bad steady-state random read performance, it at least draws the least amount of power in the process.
Meanwhile, Intel's SSD 320 does well, delivering 9x more performance at a queue depth of 32, yet only consuming 45% more power.
The efficiency of Micron's P400e is more impressive in 4 KB random writes, where it not only beats the SSD 320, but also uses less power than the Intel desktop drive.
Unfortunately, if you consider the SSD 710 as well, the more enterprise-specific model serves up two times as much performance at 70% more power.
Switching to sequential accesses, the P400e consumes slightly more power to achieve its performance edge over the SLC-based P300. However, this 0.06 W difference is really inconsequential considering both SSDs achieve around ~450 MB/s.
Intel's SSD 520 is the more energy-efficient option; it delivers greater performance and consumes less power.
The P400e nearly catches the performance of Intel's SSD 520 at a queue depth of eight when the SandForce-based model is made to juggle incompressible data. So long as you limit you scope to that comparison, Micron's new offering is more efficient because it consumes less power than the SSD 520 to achieve similar performance.
Larger block sizes have little impact on power consumption. At a queue depth of eight, 128 KB and 2 MB performance and efficiency are roughly the same.