Energy consumptionFinally we measured energy consumption with a clip ammeter. Energy consumption was taken at idle and in one of the most intensive SSD loads, sequential writes.
At idle, the M4s draw less power than the C300s, though only slightly. In load, the M4 64 and 128 GB models draw more power than their C300 equivalents. On the other hand, the M4 256 GB does very well and is on a par with the 128 GB version and therefore with significantly lower consumption than the C300 256 GB. However these figures need to be put together with write speeds to give a complete view of power draw. The following graph shows energy consumption for each 100 MB written:
By combining write speed and energy consumption during writes, you can see that the M4s are more efficient than the C300s across the board (at identical capacities). The M4 256 GB benefits from using chips with two 64 Gb dies, while the 128 and 64 GB versions use chips with two 32 Gb dies.