realistic UPS for GPU miners?

[takagari]

Looking at getting some miners up and running. And presently I live on a farm. The power here seldom goes out. But it's known to flicker enough to knock clocks out of sync etc.

With such heavy power draw from the gpu miners. What's the most effecient ups out. That could handle a 1500w or greater psu. Say a 6 card setup.

Something rack mount would be real nice.