Green IT Glossary: 80 Plus Power Supply

80 Plus LogoWhat is 80 Plus?

If you have been eying components for a new PC or server build, or perused the spec sheets on some systems destined for your datacenter or server room, you likely came across the term 80 Plus. Essentially, power supplies (PSUs) with this rating have an 80 percent or better AC (from your plug) to DC (what your computer’s components use) conversion rate when tested under load at various points.

Why is it important?

During the transmission and conversion of electricity, a certain loss of power occurs. In the case of power supplies for computers and servers (and most gear, actually), the loss translates into heat, a worrisome development that requires the consumption of more power (see where we’re going?) to drive fans to push away that heat from circuitry that doesn’t take kindly to temperature extremes. The knock-on effect is that datacenters need to vent this hot air and supply cool air, resulting in more energy costs. Note that processors, RAM, drives and mother/daughterboards generate heat too, so PSUs aren’t the only culprit.

But the real problem is that a good chunk of the electricity that you spend money on never reaches your computer’s components. So, not only are you paying to generate and expel waste heat during the AC/DC conversion process, a lot of the earth’s resources are being consumed to ultimately power nothing.

Several power supply makers think they can do a lot better, and so the 80 Plus standard was born.

80 Plus Explained

You see, typical power supplies can turn up to 40 percent of the electricity they take from the wall socket into heat, which results in cooling costs and can contribute to a shorter lifespan for your computer. 80 Plus power supplies, on the other hand, deliver more electricity and generate less heat.

In an example provided by 80 Plus (PDF), a typical 200W power supply can consume 143 watts AC to generate 100 watts DC, resulting in 43 watts in wasted heat. An 200W 80 Plus power supply only consumes 125 watts to generate the same 100 watts DC. This leads to lower energy costs to provide the same power.

Enermax Liberty Eco Power Supply

To qualify as an 80 Plus power supply like the Enermax above, it must maintain at least 80 percent efficiency at 20, 50 and 100 percent load. And there are sub-qualifications: Bronze, Silver and Gold. Bronze satisfies the bare minimum performance required to qualify for 80 Plus while Gold can achieve higher levels of efficiency – up to 90 percent in some cases.

Neat, right?

Of course, it comes at a price. You likely won’t see 80 Plus power supplies at bargain basement prices, but they are generally competitive. Savvy online shoppers will always find a good deal, anyway. In any case, the power supply is one component that you never want to skimp on so do your research for reputable PSU makers and consult the 80 PLUS Certified Power Supplies and Manufacturers list.

OEMs roll the cost of components into the final price, obviously, but you can count on cutthroat competitiveness for a spot on your desk or server rack to keep those discounts and bargains coming.

Bottom line: check for 80 Plus and enjoy the benefit of a smaller energy bill, longer-lasting gear and good old green IT karma.


by Pedro Hernandez on May 19, 2009 · 0 comments

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