Just going up to 60mm or 80mm standard size DC fans can be a huge efficiency increase in watt-hours spent per cubic meters of air moved per hour.
I am extremely skeptical of the "12x" but using larger fans is more efficient.
from the URL linked:
> Bigger fans = bigger efficiency gains Oxide server sleds are designed to a custom form factor to accommodate larger fans than legacy servers typically use. These fans can move more air more efficiently, cooling the systems using 12x less energy than legacy servers, which each contain as many as 7 fans, which must work much harder to move air over system components.