Power Supply Calculator

[myktek]

I found this on eXtreme Outer Vision.

eXtreme Outer Vision - eXtreme tools for computer enthusiasts

Click on eXtreme Power Supply Calculator.
Click on Lite Version.

Configure your system setup and then click on Calculate button at the bottom.

[GeorgeH]

According to the calculator I need a 381w power supply. I do have one that size but ...

My actual power requirement is about 100-125w (input measured with a Kill-a-watt).

[Rich A]

Originally Posted by GeorgeH

According to the calculator I need a 381w power supply. I do have one that size but ...

My actual power requirement is about 100-125w (input measured with a Kill-a-watt).

The "Kill-a-watt" device is measuring your AC 120 volt wattage. Not the wattage of the combined DC 5, and 12 volts produced by the power supply. You are comparing apples and oranges.

A typical PC power supply (for example) is rated at 6 A at 115v or 3 A at 230 volts. Said power supply can supply up to 25 A @ 5 v and 10 A at 12 v.

Wattage is a component of Amps ... So 110 watts at 115 volts is not the same as 110 watts at 12 volts.

Plus I imagine the web site calculator is giving a worst case scenario. Where every device is calculated as drawing it's max amps / watts, all at the same time. Which would be pretty rare indeed. Of course then you have to take into consideration the efficiency of the PS. Some of today's modern "green" power supplies have a very low overhead. In the old days that 110 watts could actually be only 60 percent of the actual wattage being used by the powered devices. The rest is heat and what we call "Idling current" ...which is when a PS is sitting there with NO devices drawing power. Today's green power supplies can be had up to 85 percent and higher efficiency.

[mkcitizen]

antec has one as well
they are not that accurate.


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