Actually, 80 Plus does specify different (higher) target efficiencies for 230VAC input. Not sure when they started this, it was not always so.
I agree that the Bronze Silver, Gold, Platinum categories become useless when you compare category PSUs of different power rating because of the reliance on % of rated load rather than specific watts.
In fact, those metal medals definitions are similar to defining "medal" winners and losers in the Olympics -- when the difference between best and worst is measured in less than 0.1% of the total performance (however you want to define it), why even bother? It's the obsessive competitive human desire to constantly create hierarchy -- winners & losers -- that is at the root of this.
Anyway, I'm glad andyb
brought up the topic. It's one of the the points of discussion I brought up to the creators of 80 Plus when they asked for my opinions some months before the program was launched.
Even using % efficiency is misleading, especially at the low end: At 20W load, A is 70% efficient & B is 65% efficient. 5% difference looks significant, but it turns out to be 28.6W input vs 30.8W -- just 2.2W
. But 85% vs 90% efficiency -- 5% difference -- at 500W load is 588W vs 555W, or 33W
. Another reason why they should have used WATT numbers, not percentages, right from the start.
But it probably would not have found as easy market acceptance.
It probably helps to understand how/why the program got launched:
The 80 Plus program provides a rebate of $5 or $10 for each 80 Plus approved PSU that is used in a system by a commercial system integrator. Aside from the >80% efficiency requirement, the program calls for a Power Factor of >0.9. Only active power factor correction can achieve such a high PF. The 80 Plus program, administered by Ecos Consulting on behalf of a consortium of US utility companies, encourages the use of power-efficient power supplies by offsetting their higher initial cost. Why? To quote the 80 Plus web site, "Saving a kilowatt-hour through cost-effective energy-efficiency programs is more economical than building the new generation, transmission and distribution lines that are needed to meet growing energy demands."
It was about saving the utilities money by reducing demand so that they didn't have to expand the electricity generation capacity, which is very costly. 80 Plus was one of the programs Ecos Consulting came up with to reach this goal, and the rebate $$ came directly from the utilities. As the program gathered steam, they hooked up with Energy Star and then it turned into an industry-wide thing, which is exactly what they'd hoped.
I wrote another piece when they expanded the definitions & got more commercial. 80 Plus expands podium for Bronze, Silver & Gold
The 80 Plus program is flawed in many ways, and will probably remains so, but it has definitely made an impact on overall PSU efficiency in the computer industry. 10 years ago, 70% was pretty damn good efficiency for any computer PSU. Today, the average is better than 80%. Would PSUs have become more efficient anyway? Sure, but having a standard everyone could rally around -- and were forced participate -- made it happen faster & more thoroughly. (Some old timers might recall the wild west days before Intel took a controlling role in ramming standards and protocols down everyone's throats for all kinds of things (ATX, AT, PCI, AGP, etc, etc). It was a mess... and those standards made rapid industry-wide cooperative progress possible. )