Good article but as said they missed a few tricks which could have made it the definitive article:
1. As Audigex says, just cause 500W is the max used doesn't mean a 500W or even 600W psu would be able to handle the ampage on the 12v rails.
2. No mention of the fact that all psus pretty much have their highest efficiency between 50 -70% load which means a 800W+ psu would be cheaper to run than a 500/600W psu on that last gaming rig.
3. Okay, they at least picked highish end systems but people with rigs like that tend to have more optical, hard drives, fans, water cooling loop(s) etc. I know with mine I have 2 optical drives, 4 hard drives, water pump, 7 120mm fans, fan controller etc. This would probably take that final rig to a max of 600W+
4. No mention that in decent psu reviews that as loads increase the voltages on the rails drop and the stability and ripple of the voltages deteriate as well which affects the whole stability of the system especially if overclocking. In fact if you look at extreme overclocking forums, the super high end overclocks have come from people who have modded their psu's to give 12.5v at idle and hence still 12.2v ish under load whereas most psus start above 12v and drop below 12v under high loads.
5. Although I am not convinced yet, it has been widely reported that a psu will lose up to 10% of its power per year. I want my psu to last 3 years minimum, ideally 4 - 5 years and hence cope not just with my current cpu and gpu but future ones over the next 5 years without having to buy another psu.
6. And finally for those of us after quiet systems, the fan in a psu is at it's quietest up to 50-70% load (varies from psu to psu)
Therefore, although I agree with their results, I slightly disagree with their conclusion when you take the above into account.
A 750W psu would indeed be "sufficient" for their gaming rig but as the "minimum" psu you should go for to avoid all the problems I have listed above.
