PC Peripherals How Wattage Is Measured Exactly ????

M

max_s

Disciple
HI guyz, i came up reading many reviews regarding power supplies,proccy, gpu, motherboards...etc
one thing i noticed is that...in reviews they measured the wattage on different load config. on PSU's
they measured it in 20~40~60~80~100% load and calculated its efficiency...i meant how did they managed that..suppose a psu is 500w so what is the efficiency it shud provide optimum (will it really deliver 500w to the system)....and secondly wat kind of work load wud bring 100%load on all the component..if it happens then wud psu b on 100%load then....can u name few psu u that wud fail on typical load of 80%~90% ??? :huh:
 
Efficiency is basically the ratio of the output power to the input power.Ideally it should be 1 i.e.100%

1000W power supply means it can supply power upto 1000W depending upon device connectd.It will not supply 1000W continuously irrespective of device connected,lets get that cleared first.

Say a 800W device is connected.Assuming 100% efficiency power supply will take in 800W and give the device 800W.

Assuming 80% efficiency,the power supply will now have to take in 1000W to give 800W.

Now here's another thing to worry about in practical scenario.The efficiency of the power supply will vary depending upon the load connected.

Generally,at 60% load,the psu displays its maximum efficiency.Efficiency will decrease either with increase or even decrease of the load.

Hope that clears up stuff.
 
Got my some of the doubts cleared...the how come the manufactures display effficiency 70%+ 80%+ means their psu are capable of delivering at constant 70+~80+ and wat kinda load can put system on 100% load...does that mean the psu will also be at >80% load??? wud that damage the psu???
 
Best PSU performance (balance between efficiency, regulation and ripple) is obtained between 50 and 75% of rated output, for name-brand supplies with good components.
 
max_s said:
Got my some of the doubts cleared...the how come the manufactures display effficiency 70%+ 80%+ means their psu are capable of delivering at constant 70+~80+ and wat kinda load can put system on 100% load...does that mean the psu will also be at >80% load??? wud that damage the psu???
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They have equipments to draw current from respective rails.

need not be real PC components.

as for how the manufacturer tests it is sole matter of their techniques. Some good brands test the PSUs at 50c operating temperature (more practical) and some cheap PSUs come with ratings at 25c (not unless you live in freezing areas).

here you go.. http://www.jonnyguru.com/modules.php?name=Testing_Methodology

that shall answer all your questions i guess :)
 
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