# Power consumption



## z662 (Mar 14, 2010)

I wanted to know if there was a way to view how many watts your system is pulling at a given time.  I am not interested in the maximum load that the power supply can handle, rather how many watts are being used.  Thanks


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## Sylgeist (Mar 14, 2010)

I don't think you can get that from the OS level without a smart power supply or some kind of built-in power management board. I use a product called "Kill-A-Watt" that I was given by a vendor. It plugs in between the power cord and the wall and shows various stats about power usage. You can also pull this information from most smart UPS's via the USB/serial interface.


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## aragon (Mar 15, 2010)

Only some notebooks have the necessary sensors for this AFAIK.  In those cases:


```
acpiconf -i0
```


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## Ruler2112 (Mar 15, 2010)

There was a discussion on this late last year.  I'd still kinda like to build the beast I describe...


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## z662 (Mar 17, 2010)

Cool Ill take a look at that shortly.  Thanks


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## overmind (Mar 18, 2010)

I've used a similar device to measure consumption. You plug that device into power socket and then your desktop into it.

By doing a lot of measuring I've discovered for x86 that is power consumption is proportional with cpu frequency and number of cores.

Power used is for CPU+motherboard (whthout hdd, which is 10W or less for e desktop hdd):
- AMD Geode 500 MHz, consumption 4W
- Via C4/7 1Ghz, 11W (double frequency, double consumption)
- Intel Atom N270 1.6 Ghz (single core) 25W 
- Intel Atom 330 dual x 1.6 GHZ: 33W

A dual core E2200 (2x2Ghz): 48W in idle, 78W in load.

For a CPU used in mini itx boards or notebook, cpu consumption does not grow much in load vs idle. For a desktop CPU it is a big difference.

On a quad core in X window i have 100W, if I open Firefox and then lot of tabs with websites, I have sometimes 150W.

A game that also uses GPU and CPU is 100%, on a quad and a ordinary nvidia 8500 can consume 200W-220W.

Macs are very green, in idle (not standby!) the consumption is only 14W for a Mac Mini dual core (40W in load).

(That's because the OSX, somebody installed OSX on a dell laptop and battery now holds 4 hours instead of 3 hours with Vista.)

All I've told you including consumption for a Mac Mini is based on my measurements.

But do not take what I've said very strict. There can be differences.

For example motherboard with intel Atom made by intel, asus or msi have different consumption. (with few wats difference, which is alot).

Also I've measured two mobo with Atom, same type of motherboard with different power sources. One was consuming 41W and other 37W (intel atom 330 + 1 hdd) 

All components were the same in both systems, only power source differs.

There are some UPS that have software that tells you power usage. I had one of those, but the power consumption is not precise. For a computer it told me it was consuming 14W and if I put the power metter to see how the ups consume, it show me 50W (and the ups battery was full).


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## z662 (Mar 18, 2010)

Thanks a lot, that answers my question.  I really just needed a ballpark figure.  I am pleased to see that the load is really not that high at all....Unless you are gaming on a pretty intense game. I would have thought the  numbers would have been much higher.  Makes you wonder how many people that buy those kilowatt PSU's ever use more than 1/3 of the potential.


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## overmind (Mar 18, 2010)

There's also the power consumption of the monitor.

A usual 19 inch TFT desktop monitor consume 45W.

One more thing: I've measured a computer with intel mobo and dual core and consumes 10W when is power off. A CRT 21 inch monitor powered off consume 30W (even the power button seems like to have 2 position on/off and it seems is not digital so you think that the power button is connected directly to power and is not controlling the monitor digitally.)

If you have many powered off computers but plugged in, you waste alot of power without any benefit.

A powered off TV can consume 35W.

All is relatively. You must measure yourself. A mobo with AMD cpu is not consuming any power, well that's what I've measured. That does not mean that Intel mobo consumes and mobos with AMD cpu does not consume. It all depends on manufacturers of those mobos, and motherboard type (I think).

Another thing: when you see a PC power source that has specs 400W, it should work with such load. In fact usualy the real power is 200 - 250W.

Some nvidia video cards require separate power (12V) and also require 450W of power souce (for entire system). Well some 450W as in manufacturer specs are not in fact 450W but like 250-300W, so those nvidia cards will not work.

Some computer shops that sell PC power sources nows what is the real power of a source. For a noname source when they advertise 600W, you usually get 400W (sometime worse).


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## GhettoBSD (Mar 18, 2010)

You can check out this thread for some info on my atom build: http://forums.freebsd.org/showthread.php?t=11136

More specifically:



> - Intel BOXD510MO Intel Atom D510 Intel NM10 Mini ITX Motherboard/CPU Combo
> - 2GB of DDR2 800
> - 750GB WDB HDD
> - Scythe S-FLEX SFF21D 120mm
> ...


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## ckester (Mar 18, 2010)

I'm getting similar results with my mini-ITX Atom machine (D510MO, 3GB RAM).

These make a very nice alternative to the Mac Mini.  I like OS X, but am becoming concerned about having my data in formats that are unique to apps designed for a proprietary OS.  My mini is a Power PC machine, and Apple has abandoned support for that processor.  I could either buy an Intel-based Mac and continue tracking the latest version of OS X, or I can cut my losses.  So I'm gradually moving all my stuff over to FreeBSD and open-source applications.

Interesting data here in this thread.  It looks like my LCD monitors are now my biggest power hogs.


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## overmind (Mar 18, 2010)

It would be interesting to see power consumption on a dual core x2Ghz Mac Mini with FreeBSD.

I have to intel Atoms 330 (dual core 2x1.66Ghz), one with 1 GHz ram and hard one hard drive WD blue 160GB - 41 W consumption, the other system, same motherboard, a 320G WD blue, 2G RAM - 37W consumption.    (The difference in power consuption 41W vs 37 is because of power sources, i've switched hard drives and I get the same consumption) The one with 41W in 100% cpu -> 44W, the one with 37W in 100% cpu is 41W maximum.


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## oliverh (Mar 18, 2010)

@overmind most usual TFT displays have an average power consumption of 25-45W. The bigger the more power consumption (most of the time). I have a 24" TFT display with a consumption of about 33W and a 19" TFT display with measured 25W.

>Intel Atom 330 dual x 1.6 GHZ: 33W

The latest one, D510 (dualcore/Intel D510MO desktopboard): 22W idle, about 30W under load


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