Small desktop-class fans, sure. But when you're talking 1U or 2U rack-mounted systems with high speed (>10k RPM) counter-rotating fans, they often suck tens of watts each. And usually in those systems there are at least four, sometimes six, often eight. So it's reasonable to think that bringing down overall compute load over hundreds of systems would cut out a significant, measureable chunk of energy usage in just moving air.
