For a given hashrate, the U3 uses 6.1458333 times more power(electric) than the S9.
(S9 Electric usage per hash) * (6.145833333333333) = (U3 Electric usage per hash)
Because, math.
Comparing "overall" is like saying a jet uses more fuel than a moped.

Right, I simply commented his(/her) moped<->jet comparison: "Funny to see newer generation device is like 230x times faster than previous one."
I was saying 230x hashrate because it uses more power, not that it uses 230x more power..