In the last two to three years I have had to replace the power supplies (PSUs) for my main computer with units of continully increasing wattage (650, 750, 850, and 1050 watts) at least 6 times. This are good, expensive name brand PSUs that the manufacturer has replaced under warranty. The brand new 1050 watt unit recently began causing BSODs, so I had to put the 850 W unit back in. I operate these PSUs at 1/2 to 3/4 of rated wattage; e.g., the present 850 W unit is supplying 620 to 665 wildly varying watts. Last night I was watching the GPU-Z output of the power demands of two Nvidia Geforce 570 GTX display cards, which both erratically varied between 22 and 55 Amps (at only 1 volt) as they processed Seti@Home work units. Is it possible that the switching unit of these switching PSUs cannot keep up with these wildly varying power demands and so is failing? Is it a good, bad, or neutral sign that the PSUs 12-volt rail is outputting at present 18.82 volts measured by a VOM at a Molex hard disk connector?