Odd, they have 2 batches, one with 8 TH/s and one with 8.7 TH/s which I assume is running at 550M and 600M, but they didn't update the wattage used for the 8.7 in the specs., so those that don't know will think the faster one is even more efficient than the slower one and uses the same electricity.  In reality, it probably uses about 10% more electricity.