How about this one....

[YoDude9999]

DrPoP, I forgot to mention that also this very symptom can also be related to GPUs overheating. I had a 460 that was overheating and causing the same problem. If you can positively rule out the PS as a potential problem, look at the GPU temps.

Also try Mumps idea of power re-distribution, just in case.

The PS and the newer GPUs will try to protect themselves. I think they (GPUs) are doing this by dropping the "Power Good" signal that goes back to the PS while the system is running. If, for any reason, this signal is lost, the PS shuts down without warning. PSs will also try to protect themselves from an overload condition in the same manner, but without dropping the "Power Good" signal as this protection is built into the PS itself.

Yo-

[DrPop]

Thanks for all the thoughts on this guys. Life has been crazy...I will maybe give this all another round after the PG Challenge when I can baby-sit it and see what's going on. There *must* be a reason...