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Is It Worth Investing In a High-Efficiency Power Supply?

MrSeb writes "If you've gone shopping for a power supply any time over the last few years, you've probably noticed the explosive proliferation of various 80 Plus ratings. As initially conceived, an 80 Plus certification was a way for PSU manufacturers to validate that their power supply units were at least 80% efficient at 25%, 50%, 75%, and 100% of full load. In the pre-80 Plus days, PSU prices normally clustered around a given wattage output. The advent of the various 80 Plus levels has created a second variable that can have a significant impact on unit price. This leads us to three important questions: How much power can you save by moving to a higher-efficiency supply, what's the premium of doing so, and how long does it take to make back your initial investment?"

5 of 328 comments (clear)

  1. Re:IMG Tag? by evilviper · · Score: 5, Insightful

    The real embarrassment is that /. has never supported basic tags like <sup> which would allow proper math mark-up. Instead we get all manner of mangled, unreadable blobs for comments.

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    Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
  2. Re:The Maths by SJHillman · · Score: 5, Insightful

    Not to mention reduced heat output (and potentially less fan noise due to lower heat), important in many scenarios

  3. Re:The Maths by FrankSchwab · · Score: 4, Insightful

    Your HTPC server consumes 350W? What the hell do you have in that thing?

    Mine consumes less than 65W running full blast, serves files and 1080p video. I'd say you'd save a hell of a lot more money by downsizing that HTPC rather than just getting a more efficient power supply.

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    And the worms ate into his brain.
  4. Re:Do you heat your house? by ShogunTux · · Score: 5, Insightful

    Perhaps the "pump" part of heat pump completely eluded you, since they do not defy the first law of thermodynamics as you seem to be implying.

    Heat pumps work by having a sink source off of which they are pumping the heat from or away from. Most of the ones I know happen to be geothermal, which work because the sink which they are pumping from maintains a constant temperature year long underground. So, during the summer, the heat they can extract from that source would be cooler than the air above ground, but during the winter be hotter. They do this by extracting the heat from the source sink, rather than producing it themselves.

    So in that respect, they work much like the fan does within your computer, since the air inside the case is much hotter when running than the air outside of the case. The fan can then displace that heat generated inside rather efficiently by just pushing the hotter air inside the case out, while bringing the cooler air from the room outside in without having to require an equal amount of energy to then power those fans as the equipment running inside of it, thus, like the grandparent, requiring less electric energy to power those fans than what the computer itself uses. If this were not so, then it'd make a lot more sense to completely seal computer cases, as the cooling benefit from the fans wouldn't make up for the amount of dust which they bring into the case during operation.

    So the next time you're tempted to call bullshit on a well known physics principle, make sure you double check that you're not making some stupid mistake. Or else you'll end up looking rather foolish again when someone else points out how you don't know what you're talking about.

  5. You forgot a variable by mathimus1863 · · Score: 4, Insightful

    How about reliability? I require a PSU that I know is going to

    (1.) Not die within a year of running at 50-75% load
    (2.) Not take any other components of my computer with it.

    Power supply problems are the most annoying to diagnose, because the symptoms usually show up in other components (like apparent RAM corruption, HDD stuttering, etc). I would pay $50 extra for a power supply that is *not* 80-plus if it has stellar reliability, because it means I only have to build my computer exactly once. On that note, the Corsair HX series power supplies have not only stellar reliability, but also pretty much silent. I refuse to buy anything else, and you can usually them 20% off if you watch slickdeals.

    Efficiency saves you money, while reliability saves you time *and* money. And time is a limited resource for some of us...