PSU mains power usage

I have had a good look around for how much power my PSU's are using and have got some quite weird answers. One in particular said that the mains power usage / current draw is around half of what the PSU puts out.

Now using that logic my latest - Corsair HX 1050 rated a bit below that figure it turns out would be drawing 400 -- 450 watts from the mains supply? This I find very hard to believe in view of the technology and having made a few battery chargers in my time I have never seen those sorts of figures before.

So does anyone know what mains power PSU's actually use? I know a device will only reflect the input by what it is putting out even so with the cost of power as it stands using my machines could be very costly.

http://www.newegg.com/Product/Product.aspx?Item=N82E16882715001This is the only way to know, for sure, how much your draw is.

James7679 said:

Newegg.com - P3 Kill A Watt Electricity Load Meter and MonitorThis is the only way to know, for sure, how much your draw is.

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Ok James I thought there just might be a calculator around - I'll see what I can get out here as Newegg don't ship O/S

Just as an afterthought I have a UPS on my equipment and at the moment have two machines running one with the HX 1050 an the other with a HX 650 and the readout on the screen is as in the pics so I gather I am using 316 watts and the other readout is the year usage.

There are too many unpredictable parameters to calculate exact draw.

There you go. Here's something else http://research.microsoft.com/jump/131778

James7679 said:

There you go. Here's something else Joulemeter - Microsoft Research

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Hey thanks James we must have cross posts I just realised I have a UPS that gives me a readout on the screen

But that ref you sent is going to get a try