Hardware Reference
In-Depth Information
As you can see, when supplying the same 250 watts of power to the system, the actual
amount of power used, and consequently the amount of energy wasted, varies consider-
ably. A more efficient PSU can save a tremendous amount of energy and money over the
life of a system. Because of this, I highly recommend 80 PLUS certified power supplies,
especially those earning the higher efficiency ratings.
ENERGY STAR
ENERGY STAR is an international standard for energy-efficient consumer products, in-
cludingcomputersandpowersupplies.TheU.S.EnvironmentalProtectionAgency(EPA)
introducedENERGYSTARasavoluntarylabelingprogramdesignedtoidentifyandpro-
mote energy-efficient products. The first products labeled in the program were computers
and monitors. In the years since, ENERGY STAR has become an international standard,
and the label can be found on new homes, commercial and industrial buildings, appli-
ances, office equipment, lighting, electronics, and more. Devices carrying the ENERGY
STAR logo generally use 20%-30% less energy than required by federal standards. In ad-
dition to ENERGY STAR, many European-targeted products are labeled with TCO Certi-
fication,acombinedenergyusageandergonomicsratingfromtheSwedishConfederation
of Professional Employees (TCO).
Starting in 2007, the ENERGY STAR computer 4.0 specification required the use of a
powersupplythatmeetsthe80PLUSstandard.In2009the5.0specification wasreleased
and now requires a power supply meeting the 80 Plus Bronze standard, for a minimum of
85% efficiency (at a 50% load).
Advanced Power Management
Advanced Power Management (APM)
isaspecificationjointlydevelopedbyIntelandMi-
crosoft that defines a series of interfaces between power management-capable hardware
and a computer's OS. When it is fully activated, APM can automatically switch a com-
puterbetweenfivestates,dependingonthesystem'scurrentactivity.Eachstaterepresents
afurtherreduction inpoweruse,accomplished byplacing unusedcomponents intoalow-
power mode. The five system states are as follows:
•
Full On
—The system is completely operational, with no power management occur-
ring.
