Page 1 of 1
PSU Consumption
Posted: Fri Jul 22, 2005 8:23 am
by Kills On Site
I was wondering, do PSUs of different wattages consume different amounts of power? Would a 400W PSU use more power then a 300W PSU? Assuming they were used in identical systems.
Posted: Fri Jul 22, 2005 8:15 pm
by AmIdYfReAk
yes, obviously..
Voltige X Amps = Watts
so, 300watt PSU = 120V @ 2.5AMPS
400watt PSU = 120V @ 3.333AMPS
and that is Per cycle..
Posted: Fri Jul 22, 2005 8:18 pm
by Survivor
He means does the actual usage mean anything like 300 watt psu with the pc requiring 250 using less power than the 400 wat psu with pc still requiring 250.
Edit: or you are saying that only the psu determines power consumption
Posted: Fri Jul 22, 2005 8:26 pm
by AmIdYfReAk
Well, Sorry, i was a little vague.. the power supply's do use more power when they are highervoltige ( maintain, that we are talking about Say 2 identical branded yet diffrent wattage PSU's ) But its not as much as i am saying,
the powersupply will Hold a residual Charge Determined by the system load.
most psu's will run idle at about 80% load reguardless of the system load on hand, but when puch comes to shove, they will operate at ~110% before blowing.
and somthing else to remember, Psu's are getting more and more efficent, meaning they require Much less Amp's to get the work done.
thus: if you are kickin with a 300watt PSU from say 4 years back.. and you are looking at say, a 400watt PSU right now, you would/should be getting the same power consumption on the unit's reguardless of there diffrent wattige rating.
anyway, this is all from my experance.. I'm no electricion.
Posted: Fri Jul 22, 2005 9:23 pm
by bork[e]
I don't think there are such things as electricions, could be wrong.
Posted: Fri Jul 22, 2005 9:30 pm
by AmIdYfReAk
Electricians, Pardon me..
Posted: Sat Jul 23, 2005 8:41 pm
by Magestic
The thing is, it all comes down to efficiency. If a computer uses an actual 230 watt, a good PSU will consume 285 Watt, or a bout 80% efficiency.
So it doesn't matter what the PSU is rated, just (if it can supply enough, that is) how efficient it is. You can have a 550Watt PSU powering that 230 Watt and still consuming only 270Watt or a 300W PSU powering the same system and consuming 310 Watt. (By consuming I mean drawing from the actual electricity from the socket in wall).
ATX2.01 standards require a 70% efficiency though. PSUs will vary a lot though. I seen tests where a Antec Phantom 500Watt PSU will only consume 261 Watt to power a 230watt load, while several Aopen and Nexus PSUs will consume more that 315 Watt.
You can see for yourself, buy a normal cheap power consumage monitor, should be available at any decent hardware store.