First PC Build - PSU Wattage?

Hello all! I'm getting ready for my first PC build. I have already picked out my components and am almost ready to purchase. I just have a few questions regarding power supply wattage. I used some of those PS calculator websites to determine what size PSU to get. I got my results, so here are my questions:

1. How accurate are those power supply calculator websites? Can I trust the results? (I used some from actual PSU manufacturer's websites)

2. My results averaged out to about 720W. What size PSU should I go with? Is 750 enough, or should I move up to an 850? (I have already figured for adding on later; SLI; extra HDDs; another optical drive, etc.)

3. Will it hurt your system having a PSU much larger than you actually need?

I appreciate any and all input. Thank you for your time. :)
13 answers Last reply
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  1. the website is acurate, it shows you the max power could be drawn from PSU

    all other questions are already answered in this very good toms thread
    http://www.tomshardware.com/forum/343495-28-power-supply-efficiency-myths
  2. AMD Radeon said:
    the website is acurate, it shows you the max power could be drawn from PSU

    all other questions are already answered in this very good toms thread
    http://www.tomshardware.com/forum/343495-28-power-supply-efficiency-myths



    Thank you for the help.
  3. http://www.realhardtechx.com/index_archivos/Page362.htm

    You must have some massively power hungry components for it to draw 700+ watts
  4. Power ratings on most psu are jokes. There is no standards use to establish the wattage that a psu puts out. Temperature has a big effect on output. Some brands use 20C but the case temp maybe 40 to 50C. Real output can drop by half with higher temps. Output can be peak rather than continuous. The quality of the DC output can deteriorate when the psu is pushed. So the reputation of the brand is far more important than just wattage. Check RealHardTechx.com psu review database for reviews. Also how a brand handles warrant claims are important too. So what if you get a replacement psu but all your burned out part are not covered.


    [.
  5. Outlander_04 said:
    http://www.realhardtechx.com/index_archivos/Page362.htm

    You must have some massively power hungry components for it to draw 700+ watts


    Here is my build...
    http://pcpartpicker.com/p/zfW8
  6. Goodeggray said:
    Power ratings on most psu are jokes. There is no standards use to establish the wattage that a psu puts out. Temperature has a big effect on output. Some brands use 20C but the case temp maybe 40 to 50C. Real output can drop by half with higher temps. Output can be peak rather than continuous. The quality of the DC output can deteriorate when the psu is pushed. So the reputation of the brand is far more important than just wattage. Check RealHardTechx.com psu review database for reviews. Also how a brand handles warrant claims are important too. So what if you get a replacement psu but all your burned out part are not covered.


    Thank you for the information. Going with an HX850 Corsair.


    [.
  7. we wont argue with your build :)

    absolutely u need 750W and 850 for more headroom, for safety reason

    btw hx850 is silver
    this corsair AX850 GOLD is now on promo
    http://pcpartpicker.com/part/corsair-power-supply-cmpsu850ax

    grab it fasttt
  8. Yeah I could see it needing a PSU that size.

    The website I've found most accurate is this.
    http://www.extreme.outervision.com/psucalculatorlite.jsp
  9. sewerslider said:
    Here is my build...
    http://pcpartpicker.com/p/zfW8


    850 watts looks ideal to me .

    How many monitors are you using though?
  10. The HX850 is very good but the AX850 for less money is excellent.
  11. Outlander_04 said:
    850 watts looks ideal to me .

    How many monitors are you using though?



    I will be running 4 monitors. 3 X 24" monitors and 1 X 40" LED TV
  12. AMD Radeon said:
    we wont argue with your build :)

    absolutely u need 750W and 850 for more headroom, for safety reason

    btw hx850 is silver
    this corsair AX850 GOLD is now on promo
    http://pcpartpicker.com/part/corsair-power-supply-cmpsu850ax

    grab it fasttt



    Thanks for the heads up! I got this AX850 ordered!
  13. Thanks for everyone's help and input. Much appreciated. :)
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