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Do PSU's Scale Down?

Hello,

I am considering picking up the highly rated XFX 750W Black Edition PSU (Rebadged Seasonic), problem is that I will not be using anywhere near 750W for at least a year I would say.

I plan to go with an i5-760 and a GTX 460 1GB, and eventually step up to an SLI config with 460's.

This means that I will likely never push this PSU to anywhere above 650W and probably not anymore than 450W for a year or so.

I realize that I could just buy a lower Wattage now- but don't want to hassle with an upgrade later and really like the reviews that this (http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story5&reid=184) , Seasonic X#50, and Corsair #50HX recieve. Plus 80 Plus Silver is nice!

So the question is, am I actually wasting loads of electricity (and defeating the purpose of 80 Plus) by getting more power than I will use? Or, is the hardware smart enough to only provide the amount of power that is being drawn by the components?

Sorry for the noob question- but I think one of the experts here have a cut and paste for this type of question.

Thanks!
5 answers Last reply Best Answer
More about scale down
  1. It will work fine, it will only put out the load that your PC needs and you will be ready for your SLI upgrade. According to this test the efficiency of that PSU is highest around half load http://www.hardocp.com/article/2010/04/20/xfx_black_edition_750w_power_supply_review/4
  2. PSU's don't actually scale down, the parts draw power from the PSU, they are normally programmed to scale down (CPU, GPU, HDD) when needed. So when not on load, the parts draw lesser power. Eventually drawing lesser power from the PSU on a whole.
  3. To reword the question:

    Would you say that my electric bill would be *less* using this PSU with 1 card and ~450W worth of draw, than it would be with a near full load of 2 cards and ~600W draw?

    Thanks for the replies, best answer will go out after this
  4. Best answer
    katiklysm said:
    To reword the question:

    Would you say that my electric bill would be *less* using this PSU with 1 card and ~450W worth of draw, than it would be with a near full load of 2 cards and ~600W draw?

    Thanks for the replies, best answer will go out after this

    Yes, not that it would be very noticeable.
    You would have to have quite a few peripherals to pull the kind of loads you're talking about
    http://www.anandtech.com/show/3809/nvidias-geforce-gtx-460-the-200-king/17
  5. Best answer selected by Katiklysm.
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