I think I just blew a 1200W power supply powering 2x Nvidia 295's just 18 hours after I started GPU mining. (At least I hope that is all I blew).
It tripped the circuit breaker.
What model PSU is it?
What does reference and non-reference mean in this context? And how does that effect wattage?
A reference GPU uses the 'stock' ATI / Nvidia board and heatsink, non-reference cards typically use boards that may restrict overclocking (By locking the voltage, for example) or they may have a custom cooler fitted.