# Power Supply Wattage

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Hello,

I will be putting together a PC.  How do I determine the Power Supply
wattage needed?

Talal Itani

## Re: Power Supply Wattage

Good engineering design suggests that the supply be rated at double (or
more) the actually power being drawn.
Your typical PC today should have at least a good quality 400 watt supply.
If you have a lot of harddrives and/or
a high-end video card...a 450 to 500 watt supply is in order.

If you have any doubts...you can always go higher...it will not hurt

--
Posted via a free Usenet account from http://www.teranews.com

## Re: Power Supply Wattage

You don't.  Wattages are speced like cough medicine.  A supply rated
at 230 watts from a responsible manufacturer could also be speced at
325 watts by one hyping a product only on watts and dollars.  They
just forget to mention what they are measuring.

Determine the current rating for each voltage of each peripheral -
and then sum up that current.  Then review a supply's current for each
voltage.  Supply must meet or exceed that current rating.

Then you move on the other essential fact: does it come with a long
list of numeric specifications?  If not, then what else are they
'forgetting' to include in a supply.  The functions performed by a
supply are quite numerous.  Many essential functions are 'forgotten'
when selling to computer assemblers where knowledge of electricity was
not required to become certified.

Sum up current consumption for each voltage.  Verify that nearly a
full page of numeric specs are provided.  Suddenly many supplies no
longer make the cut.

## Re: Power Supply Wattage

Talal Itani wrote:

Your processor choice is actually pretty low power. The size of power
supply, could be influenced to a greater degree, by the video cards
you use. A couple 8800GTX at 2 x 145W is a lot more significant than
65W for an E6600. When you have details for your build, post a parts

Paul

## Re: Power Supply Wattage

Power Supply Calculator Go to site and click 'Start Calculator' 'Power
Supply Calculator - Journey Systems. LLC. Providing Custom PCs, Servers,
Laptops, Workstations, Gaming PCs, Quality Custom Computers with 3 Year
Warranty' (http://www.journeysystems.com/?powercalc )

Yike's, were did that extra line in the address come from??? That
at the top of the page.

Davy

## Re: Power Supply Wattage

Talal Itani wrote:

Here's one power calculator:

www.extreme.outervision.com/psucalculatorlite.jsp

About every power calculator I've seen gave estimates that were much
higher than needed.  SilentPCreview.com took power and amp
measurements of several computers and found that actual needs were
much more modest thant he calculators estimated:

www.silentpcreview.com/article265-page1.html

Unfortunately power supply brands vary greatly in how accurate their
ratings are, and JonnyGuru.com (he tests lots of PSUs) found that
Powmax Assassins rated for 500W failed at 200-300W, while a Fortron/
Sparkle rated for 350W was able to put out 500W for a while.

If you're using a very fast graphics card, you may want to see if the
power supply is SLI approved by NVidia or Crossfire approved by ATI.