mentioned go out for bids for their parts and buy from the low bidder. In short there are a lot of crappy power supplies out there that can't really supply their rated wattage for very long. The real crap stuff seemed to start showing up in the 300 Watt Power Supplies, when demand and competiton was high.

If you simply scan these forums a huge portion of the threads include "replace the power supply" when having flaky performance..

The four year one is nothing to worry about. To do a thorough analysis would require detailed knowledge of what is in each computer and what power supply ratings, max and nominal are.

If you have one particular sysem that has blown a number of power supplies, Robert Proffitt has posted the experience that his shop has had re such. Basically it is the fact that the mobo's have defective capacitors on them. There was a major incident about three years ago where a huge batch of defective capacitors got into systems. Robert can give a link to the article on the subject.

And, of course, some of those capacitors get put into power supplies and fail there.