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Power Hardware

Is It Worth Investing In a High-Efficiency Power Supply? 328

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

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  • Quieter and cooler (Score:4, Interesting)

    by Manfre ( 631065 ) on Thursday December 13, 2012 @08:13PM (#42282377) Homepage Journal

    Higher efficiency means less waste heat coming from the power supply, so its fan can run quieter.

  • by OneAhead ( 1495535 ) on Thursday December 13, 2012 @08:17PM (#42282423)
    Get your head out of your ass. Most electric heating is done with heat pumps. A heat pump pumps more heat into your house than the electric energy it consumes (that's why it's called that way). Heating by burning something is also more efficient than dissipating electric energy because you're cutting out conversion (see Carnot efficiency) and transportation losses.

    And in the summer, if the AC is on, inefficient appliances make you lose double: once by consuming more electricity than they should, and a second time because the AC needs to consume energy to pump the heat out of your house.
  • Re:More maths (Score:5, Interesting)

    by sdguero ( 1112795 ) on Thursday December 13, 2012 @09:19PM (#42283009)
    I used to test server and PC power supplies for a living (until 2009). I do NOT recommend running at 50% load unless your PSU is a cheap turd and you are worried (rightfully so) about component failure. 80-90% load will give you better efficiency, a higher power factor, and less harmonics. Fyi, as a residential electricity customer you don't really have to worry about power factor or harmonics much but large companies can be charged by the utilities for abusing the infrastructure with a ton of shitty/under-utilized PSUs. Since the company I used to work for sold into enterprise, we were very interested in PSU performance and matching up components for efficiency.

    At home, I run a decent 350W PSU now, and my system draws about 200W of DC power under load (i.e. gaming) with my components (single Intel 2500K CPU, 8GB RAM, ATI 7870 GPU. 1 HDD and 1 SSD) and around 130W when surfing the web or working. I literally couldn't find a decent, well priced PSU with lower DC power output when I built the machine 18 months ago. It cracks me up when I see guys putting 700W power supplies into their gaming rigs that never draw more than 300W (and none seem to understand the difference between AC power draw from the wall and DC power draw of the components in their system, which is what the PSUs are rated for). It's basically flushing money down the toilet in multiple ways.

    Just my $0.02...
  • Re:More maths (Score:5, Interesting)

    by rwa2 ( 4391 ) * on Thursday December 13, 2012 @10:29PM (#42283465) Homepage Journal

    Yeah, I used to get the cheapest PSU I could. But after I somehow inexplicably fried some of my expensive components, like my GPU, I decided to drop in something a bit better.

    When I dropped another $250 on a replacement GPU, I also decided to shell out real money for a nicer PSU and put my old PSU out to the pasture... in my kids' cobbled-together box.

    Ended up going with a SeaSonic, since that's one of the brands that tend to be recommended by the Ars Technica Budget / Hot Rod box guide.

    I wish I could find it, but there was some PSU snob site that went into all of the power benchmarking and provided pagefulls of data and charts like the other sites that benchmark CPUs and RAM. They managed to point out all the ways my old PSU was deficient and sorta almost turned me into a PSU snob as well.

The unfacts, did we have them, are too imprecisely few to warrant our certitude.