Thank you for your input mindless1. But I have one more question, if I may. Since all PSU's that closely follow ATX 2.03 standards are designed to supply sufficient power for the +12V rail, and that there is no new technique to get more amps there, is this also true for the new, high quality retail PSU's that are coming out with labels that spec 33A and 36A for +12V? New PSU's like the Enermax 465W EG465P-VE(FM), Antec 550W TRUE550 EPS12V, or OCZ 470W PowerStream. Spending $92 to $116 is a lot to waste if we can get the same out of a $33 Forton/Sparkle 300W FSP300-60ATV which only specs +12V/18A. And yes, I know Forton/Sparkle is famous for underrating their specs, but I'd be amazed if that's true.
The key here is "high quality". Those are not necessarily all high quality power supplies. Fancy grill, casing, or cable sheaths are beutifications meant to promote sales to those who are tricked by eye candy. A pretty power supply
might be good, but the two qualities (looks and power) are not interdependant. Many reviews of questionable power supply put about a 250W load on a unit claimed to be "400W" or more, then give it high marks... it is a disservice to the community to do so, but we all know there can be alterior motives for doing so, let alone lack of proper testing methodology.
Enermax is NOT a high quality power supply, even their own specs clarify that their units are only MTBF rated at 70% output @ 25C... In other words, their wattage specs are peak values only, not sustainable. If we filled an Enermax with plastic explosive it would have a quite high peak output too :evil:
We can expect some name-brands, models, to exceed Sparkle 300W's output. The name on the unit's label should be considered since primary power supply manufacturers (which BTW, Enermax and Antec aren't) have worldwide reputations to maintain, generally they do not put their own name on a label when the specs are, umm, less than accurate.
Frankly, it's doubtful that all but a few people actually need over 14-18A on 12V rail, and those users, having very high o'c Prescott P4 and a ton of HDDs (or some other atypical load like peltiers). Those that do need this much power are in a small minority, as are the power supplies actually capable of sustaining this output. Lower volume manufacturing, the higher liability for manufacturer to warrant a unit for ~ 500W output, and the component grades used to squeeze that high a power density into such a small, PS2 form-factor power supply, all contribute to driving up price for higher wattage units. Certainly two 300W Sparkles are capable of more output than almost any $100 power supply... and so it goes for many commodity items, that the lower volume highest spec parts command premium prices. This must be countered by the minimal true output actually needed to promote an acceptible service life of PSU, and system as a whole if PSU has important saftey shutdown circuitry missing or so poorly designed that system components are are risk when PSU operates in degraded fashion.
If a user actually needs higher than normal 12V amps (considering that normal IS a P4 or Celeron using 12v... intel does have the majority of the market) then that user will have to qualify a unit themselves or seek detail of qualifications made by others, that units were tested to actually ouput under similar load, rail distribution, and sustain that output over a period of time. Running a test for a few days tells nothing of whether that PSU would run like that for a few months or longer and what happens when it fails.