AC Power Consumption of Computers

**Harvey** · 07-12-2007, 04:27 PM

Re: AC Power Consumption of Computers

There's a number of power supply calculators on the 'net, like this one http://www.extreme.outervision.com/p...ulatorlite.jsp

Pop in the details of your system and it gives you a rough idea of the required PSU rating.

**linuxguru** · 07-13-2007, 12:44 AM

Re: AC Power Consumption of Computers

Per Hansson, great work there! As you said, some surprises for me:

1. The S3 state consumption on the Xeon is higher than I expected at 36W, but I suppose that's OK when you consider that PSUs are very inefficient at extremely low loads. That 36W reflects power drawn by the PSU fans, +5Vsb, bleeder resistors, etc.

2. The Xeon 3.2 GHz running cooler than the Opteron 170 at full load is also a bit of a surprise to me.

3. The Geode NX is less efficient in comparison to the Epia, but there's a bit of Apples and Oranges here - the EPIA ia also much slower. However, both are still excellent choices for appliances, firewalls, etc.

The results give a lot of confidence that I can use a 300W Delta PSU for just about anything I could possibly want to put together, even a dual-socket Xeon or Opteron.

**Per Hansson** · 07-13-2007, 04:08 AM

Re: AC Power Consumption of Computers

Harvey; those calculators are always wayyy off

I jotted down the info from my Opteron, it said 400w, the Opteron uses 190w when everything is loaded max...

I'm not saying you should go out and buy a 200w PSU and run it on that, however I made this post to put some perspective on things (now that 1kw PSU's are becoming common on the market!)

linuxguru; yea, all those systems you listed suprised me, especially the EPIA only using 24w idle, that is really really good for the performance you get from it... (btw, I forgot to mention but it has a 128mb memory stick I think)

That the Xeon uses so much power idle is not so strange, it has remote diagnostic stuff in it, you can dial into it when it's soft off and power it up, run diagnostics etc...

The Geode NX was a bit of a letdown, I built it to replace my other firewall with low power consumption in mind... Perhaps I went overboard with using a too good CPU (that Geode NX is really a Athlon XP CPU...)
Plus it's BIOS sucks, it does not support AMD PowerNOW! so I had to test it with a third party tool from Windows, nothing decent available for linux that I have found...

**yanz** · 08-06-2007, 08:57 PM

Re: AC Power Consumption of Computers

Very informative post there, Per..

**Per Hansson** · 08-07-2007, 01:23 PM

Re: AC Power Consumption of Computers

Yea, crap layed out though but I'm to lazy to make it nice... :|

**willawake** · 08-07-2007, 02:48 PM

Re: AC Power Consumption of Computers

Its interesting also in respect of UPS sizing. I have always tended to oversize them but i am thinking 500va is probably quite acceptable for office/typical home use with 17" tft.

**burebista** · 08-12-2007, 01:42 AM

Re: AC Power Consumption of Computers

Originally posted by willawake

[...]but i am thinking 500va is probably quite acceptable for office/typical home use with 17" tft.

APC Smart-UPS 420 here. No problem at all with 19" TFT hooked in.
My results measured with a Kill-A-WAtt device.

Configuration:

CPU: AM2 X2 3800+
MB: ABIT KN9
GPU: BFG 7900GS OC
MEM: Corsair VS1GBKIT667D2
HDD: WD 2500KS
DVD-RW: LG H10N
PSU: Seasonic M-12 500
CASE: SLK3000B with TriCool on low

Frequency and voltages:

Idle/medium load CPU 800 MHz Vcore 0.900V, GPU 250/660
Full-load CPU 2GHz Vcore 1.125V, GPU 540/660

Power off-----------------------6W
Boot-------------------------124W peak
Idle---------------------------67W
Watching a movie--------------71W
SPi----------------------------93W peak
S&M CPU Test----------------108W peak
ATITool 3D View--------------118W peak
S&M + rthdribl----------------128W
S&M Power Supply test-------135W peak
PFC between 0.93 si 0.98
TFT Iiyama ProLite E1900S-B---40W
APC Smart-UPS 420------------25W

So in full-load at 80% efficiency for M-12 500 my computer needs only 108W.
What the heck I'm doing with an M-12 500?

**Per Hansson** · 08-12-2007, 03:22 AM

Re: AC Power Consumption of Computers

Welcome to Badcaps burebista, I guess you're coming from jonnyguru site?

Thanks for your input about your computers power draw also
There is one thing we should keep in mind, Spectre, the HardOCP PSU reviewer guy has found that the Kill-A-Watt is not accurate. I.e. it showed him on some PSU's that the PSU was drawing less then the Sun-Moon 8000 load tester was pulling in DC. A PSU with above 100% efficiency? I think not :P

http://www.jonnyguru.com/forums/showthread.php?t=2284
http://www.jonnyguru.com/forums/show...9&postcount=13

I also do not know if my Etech PM-300 power meter has the same issue, will have to try to figure this one out before posting too many more numbers

**burebista** · 08-12-2007, 02:20 PM

Re: AC Power Consumption of Computers

Originally posted by Per Hansson

Welcome to Badcaps burebista, I guess you're coming from jonnyguru site?

Thank you. Yep, it's me.

Long time lurker here, member from a while, but no posts because I'm not so good in electronics.
/OT

**willawake** · 08-12-2007, 02:37 PM

Re: AC Power Consumption of Computers

well dont be afraid to post, not everybody is good at electronics here

AC Power Consumption of Computers

AC Power Consumption of Computers

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