PSU efficiency

[drums101]

Ok so I just got a device to measure the power draw of my computers from the wall. I was wondering how efficiency works with PSUs. I have a PCP&C 750watt ilencer PSU rated at 83% Efficiency....So does this mean that the PSU can only pull 750 watts from the wall and really only deleiver 83% of that which is 623watts? Or does this mean that it draws 903watts from the wall and because it is 83% efficient it outputs 750 watts? Thanks

 

[mindless728]

750w means it can provide 750w of power to the computer and with 83% efficiency you would be drawing 903w from the wall

though keep in mind that the psu will only draw the amount of power that your computer needs, so if you only need 400w it draws 430w from the wall

 

[drums101]

yea thanks that is what i thought i am just trying to calculate if i can handle two gtx 480s but i know i cant unless they release less power hungry revisions....the max i saw at the wall with futuremark and prime95 going was 758 watts and that was just a spike...but my psu has a peak output of 825watts so then it could handle spikes up to 994watts off the wall so in theory i have a good amount of headroom with this psu and my 2 285s now a lil over 200watts i think i need to get an average watt reading at load