power cunsumption

Bill Sturgeon
Bill Sturgeon
Joined: 25 Aug 05
Posts: 13
Credit: 132,911
RAC: 0
Topic 189999

How do I calculate how much power my computer is consuming? I have heard many things from many people, some make sense, and some don't, can somebody tell me the truth? From what I understand there is ineffeciency in the power supply? I have been told because I have a 480w ps, then I am consuming 480w? that seems pretty bogus to me. PLEASE HELP!!!

Keck_Komputers
Keck_Komputers
Joined: 18 Jan 05
Posts: 376
Credit: 5,744,455
RAC: 0

power cunsumption

Power supplies are rated at their maximum output, not the normally expected draw. In general a CRT type monitor will consume more power than the rest of the system.

Hopefully someone will come along with a link to a web site with some estimates.

BOINC WIKI

BOINCing since 2002/12/8

Landroval
Landroval
Joined: 20 Sep 05
Posts: 8
Credit: 18,885,204
RAC: 23,695

RE: How do I calculate how

Quote:
How do I calculate how much power my computer is consuming? I have heard many things from many people, some make sense, and some don't, can somebody tell me the truth? From what I understand there is ineffeciency in the power supply? I have been told because I have a 480w ps, then I am consuming 480w? that seems pretty bogus to me. PLEASE HELP!!!

The software monitor on my UPS says I'm currently drawing 211 watts running my desktop machine, 17" CRT monitor, DSL modem, and base for cordless phone. (Other stuff plugged into it, but they're all off at the moment.)

Removing the monitor from the UPS drops the power draw to 140W.

The "If your power supply is rated for X watts then that's how much you draw" is incorrect.

Sorry I don't have a link for more detailed info; a single data point may be better than nothing, but not by much.

Winterknight
Winterknight
Joined: 4 Jun 05
Posts: 482
Credit: 92,289,309
RAC: 229,024

The only link that shows

The only link that shows power consumption figures for various computers that I know of at present is at Tom's Hardware.

We recently had to upgrade the PSU on my sons computer recently, and when looking at reviews, the best psu's can be about 80% efficient, so if the computer, mobo, cpu, etc etc is drawing 160W from the psu then the PSU will require 200W from the wall socket. (Intel ATX spec only expects PSU efficiency of 60%)

The computer internals will only draw the power it requires from PSU. And you should always have some power in reserve for future upgrades. Also items with motors in HDD, DVD/CD, fans need more power to start from rest than when running, by a factor of about 3.

@Landroval 71watts for the monitor seems low, I would have expected figure closer to 100W, is the 140W for the rest of the equip when crunching or at 'rest'?

Andy

Cupojoe
Cupojoe
Joined: 24 Feb 05
Posts: 23
Credit: 33,068,058
RAC: 0

RE: I have been told

Quote:
I have been told because I have a 480w ps, then I am consuming 480w? that seems pretty bogus to me. PLEASE HELP!!!

That is indeed bogus. A switching power supply (such as in computers) outputs power in direct proportion to the demand put on it. There are two ways I can think to calculate a system's power draw. First, is by putting an ammeter between your system and the power outlet (this is similar to what Landroval's UPS does), then multiplying amps times volts (if you can get an accurate ammeter, this is probably the most accurate method, as you would be able to check actual power consumption under various conditions, such as idle or full CPU load, etc.). The other way is to get an accurate assessment of how much power each of the components of your system consumes (remember that if your CPU is going full-bore on a program like Einstein@Home, it will probably be close to its specified maximum power consumption, and if you're overclocking, it will be drawing even more power than that), then factoring in the power supply's efficiency rating to get the total power draw.

Paul D. Buck
Paul D. Buck
Joined: 17 Jan 05
Posts: 754
Credit: 5,385,205
RAC: 0

I usually use the "How much

I usually use the "How much did SMUD charge me this year for electricity" method. :)

Others have basically stated the efficiencies you might expect. In general, having a reserve in power supply capacity helps for those "surge" changes that can occur. One of the causes of system instability is lack of capacity in the PSU, so, sudden demand, no reserve, system reset ...

You can also use the power meter in some cases to get a feel for the "draw", no computer, check draw, turn on computer, let it stabalize, check the draw.

JaRski-S60R
JaRski-S60R
Joined: 21 Mar 05
Posts: 1
Credit: 26,269,652
RAC: 4

RE: How do I calculate how

Quote:
How do I calculate how much power my computer is consuming? I have heard many things from many people, some make sense, and some don't, can somebody tell me the truth? From what I understand there is ineffeciency in the power supply? I have been told because I have a 480w ps, then I am consuming 480w? that seems pretty bogus to me. PLEASE HELP!!!

I've got this PSU so I can see how much the unit is "sweating and at moment with CPY running at 100% (P4 3.4ghz) it shows ±250Watts (that is without my monitor and mouse (both got there own supply))
http://www.coolermaster.com/index.php?LT=english&Language_s=2&url_place=product&p_serial=RS-450-ACLY&other_title=+RS-450-ACLY+Real%20Power%20450

Bill Sturgeon
Bill Sturgeon
Joined: 25 Aug 05
Posts: 13
Credit: 132,911
RAC: 0

Thanks for the info guys,

Thanks for the info guys, very helpful. I am running a coolergiant 480 in my main machine, no probs supplying power to my system, it just didn't make sense to me that it is drawing 480w all the time. I (you) can tell by the heat a ps exhausts depending on load. If the energy is not going to run the components, and it is not being converted to heat, then where was it going if it was always consuming that much power? That sure didn't make sense to me. Thanks again, gotta get to work.............Bill

Thierry Van Driessche
Thierry Van Dri...
Joined: 9 Feb 05
Posts: 210
Credit: 229,929
RAC: 0

An interesting link that

An interesting link that calculates for you in less then 1 minute the needed power:
Power Supply Wattage Calculator (for Intel and AMD)

Greetings from Belgium
Thierry

Landroval
Landroval
Joined: 20 Sep 05
Posts: 8
Credit: 18,885,204
RAC: 23,695

RE: @Landroval 71watts for

Message 18008 in response to message 18002

Quote:
@Landroval 71watts for the monitor seems low, I would have expected figure closer to 100W, is the 140W for the rest of the equip when crunching or at 'rest'?

Crunching. And the 70W difference seemed a little low to me as well, but that's what the UPS is reporting.

Brian

Winterknight
Winterknight
Joined: 4 Jun 05
Posts: 482
Credit: 92,289,309
RAC: 229,024

RE: .... There are two

Message 18009 in response to message 18003

Quote:
.... There are two ways I can think to calculate a system's power draw. First, is by putting an ammeter between your system and the power outlet (this is similar to what Landroval's UPS does), then multiplying amps times volts (if you can get an accurate ammeter, this is probably the most accurate method, as you would be able to check actual power consumption under various conditions, such as idle or full CPU load, etc.)....

Unfortunately you don't get an accurate current reading this way because the current waveform is not a sinewave, also the current and voltage waveforms are not in phase because the PSU is not a purely resistive load.

This probably why Landroval's UPS is reporting wrongly, [edit] the accurate quoted output of UPS devices is the VA reading not the power reading [/edit].

Andy

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.