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Power consumption of a psu

Last response: in Systems
July 10, 2010 2:57:07 PM


My question is: if you have a system that uses like +-500 watt and you buy an psu of 700W, is your psu going to use less then 700w for your system or is it always going to use 700w
i want to put this in my pc:
AMD AM3 Phenom II X6 1055T 2.8GHz BOX
ASUS ATI 5850 Direct CU 1GB DDR5 voltage tweak ed.
Kingston DDR3 4GB 1333MHz (2x2GB) CL9
I know that antec tp-550 will do the job but i dont know how much noise it makes. If a psu of 700 watts does use less then 700w then im going to buy the cm 700w silent pro because i know that will quiet.

I'm a bit new with psu's.
I hope you guys can help me.

More about : power consumption psu

July 10, 2010 3:11:22 PM

Your system will only draw what the hardware requires. The size of the PSU does not effect how much power is drawn, kinda. :p 

It also depends on the efficiency of the PSU; PSU's are more or less efficient at different loads, so that's the only way a larger PSU could effect the power drawn.

In your case, it will not draw 700w, but some number less than that.
July 10, 2010 3:15:25 PM

The power supply is going to use what ever load is on it divided by the efficiency if the load is 500watts and the efficiency is 80% it is going to use from the wall 500/0.8 = 625watts.