Please don't believe KnC's lies. Here is an independent report about SP30 power consumption:
To be fair, that's an extreme case by running highest possible voltage. Very few people will be able to run their SP30 at 258V. Feel free to post efficiency at 110V.
As far as I can remember, efficiency at 110V was actually better than at 240V, minersource confirmed the same efficiency numbers at 208V.
Total hashrate was a little slower at 110V (which has obvious downsides).