Extreme.outervision.com psu calc, what wattage does it show?

a 500 PSU with 82% efficiency will draw 610 watts (slightly rounded up)

"efficiency" mean how much of the AC power it draws from the wall it will be converted to DC power. the rest is dissipated as heat. remember a byproduct of energy is heat; more on that in a second.

if you what to know how much a PSU will draw from the wall at a specific load, efficiency slightly varies upon 20%, 50% and 80% loads, take the "rated" power and divide by the efficiency percentage. ie you see a 650 watt PSU that will be 83% @ 100% load.

650/0.83= 783 watts from the wall

to find out how much the system uses, such as delluser1 did with the draw from the wall being 441 watts and the PSU is 86% eff, just multiply the usage (441 watts) by the efficiency (86%):

441*0.86= 379.26 watts used for the system. (380 watts rounded up)

a TDP of a graphics card or cpu ect. is not how many watts it will actually use. as i mentioned before that heat is a byproduct of energy thermal design powerback is the measurement of how much heat a component needs to dissipate (i may not have worded that entirely correct). all/many manufacturers allow a safety margin.

so in other words a gpu with a TDP of 120 watts with proper cooling; will be able to handle the heat produced by 120 watts of power (energy). many cards won't hit that power point by staying under the safety margin while others may exceed it with better cooling. so the TDP is not the actually power usage but it will get you in the ballpark. finding a review or testing from a reputable web site or a post from a trusted member that is active on a forum would provide better details.

also the recommendations from a manufacturer as to the minimum PSU requirements take into consideration what a power hungry system would need; a 130 watt cpu, several hard drives, a handful of case fans (a fan itself can vary from a 1.5 watts to up to 10) and chipset that can draw 200+ watts itself (an overclocked FX-8350 will hit 180 watts alone!). again they make recommendation to allow for a safety margin. it is best to know what your system needs; an FX-8350 system would need a 550 PSU whereas an i3 only sips enough for a 450 watt PSU.


hope this helped w/o getting to "wordy" or confusing.