Power Draw

gropingmantis

gropingmantis

gropingmantis

Soldato
Joined
5 Dec 2010
Posts
3,397
Quick question. Is power drawn from the wall indicative of the power required by your PC?

I recently bought a power monitor and no matter what I do I cant get my rig to pull more than 260 Watts from the wall.

When I put my specs into a PSU Wattage calculator I tells me I should be using a 400W PSU minimum.
Now, I realise that these calculators can be a bit off but that seems a long way off.
 
Yeh that would be right as if I remember correctly (feel free to correct me if im not)
A UK plug socket gives out 240Volts, so would that not be about right?
 
gropingmantis said:
But does that mean I could happily use a 300W PSU??
Click to expand...

No you will still need a PSU that is big enough to cope with the amount of
hardware that you are putting in the system. If the calculator says you need
400watts then I would get a 500watts to be on the safe side.
 
Wait what? But Watts is a measure of power and Voltage is a measure of energy transfer and the equation is P=IV so surely the Wattage from the wall varies with the current that your hardware is drawing and more or more power hungry hardware = more current drawn = more power from the wall? Surely?
 
gropingmantis said:
But does that mean I could happily use a 300W PSU??
Click to expand...
Yes, but it's best to leave a little headroom however, I'd go with a 400W or 430W unit made by someone such as Seasonic. :)

Shadz said:
Yeh that would be right as if I remember correctly (feel free to correct me if im not)
A UK plug socket gives out 240Volts, so would that not be about right?
Click to expand...
Watts and Volts are not the same... A kettle uses 3000W from a 230Volt wall socket...
 
panyan said:
with a lower power psu, usually it is less efficient as it is geared at a budget market so you;d have to take into account the increased inefficiency of the more budget psu
Click to expand...

Yes I was curious as after selling my AX 850 I am back on my CX 400 and was looking for another PSU as the CX 400 only has one 6+2 pin PCI power cable.

If I were to overclock my CPU (i5-2500K) and get a silly powerful GPU (580 or whatever the new one will be GTX680???) do you reckon I would ever go over 500W?

I've been looking at the FSP Aurum series as they are 80+ Gold and can fit in an SG07/08 and they come in 400, 500, 600 and 700 Watt flavours and I wasn't sure which one to get. Thats why I bought the power monitor and was stunned by how little power was using even whilst trying to burn a DVD, run Prime and Furmark all at the same time.
 
Even with furmark?

The funny thing is, a PSU is 85% effiicient (at best), so your components actually consume around 220-230W. SOme peeps reported 350W with a gtx 480, so that sounds about right.
 
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What did you have running to stress the system?, i've just ran both prime and 3dmark 11 at once and peaked at 480w (msi power calculator wasn't far off and said 490w) using the rig in sig, sound card, 2 hdds and 1 ssd.

I'm using a strider gold 750w.

Edit - nevermind i seen your later post.
 
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my uni computer (see sig) used 130W when doing general things, and ramped up to 250W when playing games and stressed - i have yet to measure the home rig :p
 
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