Solved

Measuring power draw from a computer

Posted on 2004-10-06
6
946 Views
Last Modified: 2013-11-15
How could I go about measuring the actual power consumption of a PC after it is built?

For example, if always use a 350w power supply, is that number the maximum it can supply? If my hardware specs are light (few if any PCI cards, integrated motherboard, Celeron 2.0GHz CPU), what am I actually using?

The reason that I am asking is because I want to use a reasonably sized, inexpensive UPS but do not want to create an unsafe condition. I am only trying to protect against brownouts and momentary power outages.
0
Comment
Question by:wmilliga
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 2
6 Comments
 
LVL 69

Expert Comment

by:Callandor
ID: 12240954
Wattage calculator
http://www.jscustompcs.com/power_supply/

The wattage rating of a power supply is the maximum number of watts it can output.  This, however, can take the form a lot of current on some rails and very little on others.  The 12v rail is usually a good indicator of how good the power supply is, because it is difficult to get a lot of output there if the supply is cheap.

You should consider a UPS from ebay, where you can get an APC 1400VA unit for a little over $200 plus shipping.
0
 
LVL 96

Accepted Solution

by:
Lee W, MVP earned 250 total points
ID: 12241214
Callandor - cool link.  

Yes, the wattage on the power supply is the maximum watts it will provide.  I've found that most computers (P3s and P4s) use ~175 watts on average.  If you run SETI@HOME often, then the use will increase.   I wanted a definitive answer to this myself and found a cheap device that gave me answers - http://www.p3international.com/products/special/P4400/P4400-CE.html  You can find them on e-bay (search for "kill-a-watt") for $15-30.  Very handy.  I use it frequently.  I've found that: a P3 1GHz, 512 MB RAM, 3 hard drives, DVD Writer, no monitor, AND a 27" TV, VCR, Cable box, and Stereo ampliflier (on with volume at reasonable levels uses ONLY 250 Watts of power using this device.  I also connected it to a Single outlet that a 700 VA UPS was connected to.  That UPS, with power strips, supported 2 PCs (P4 2.8 & Celeron 2.8), full tower systems, a laser printer in standby mode, Three monitors (one 19" and two 17") as well as a small network switch and a portable phone, 2 PDA chargers, and a small VoIP box from Vonage were using 500 Watts.

0
 
LVL 3

Expert Comment

by:RyanCh
ID: 12518028
Unfortionately I havn't seen this table updated, but there are several ways you can guestimate how much power you're using.
http://www.microsoft.com/nz/presscentre/articles/2001/august-01_consumption.aspx

Here is an interesting article to read:
http://www.firingsquad.com/guides/power_supply/page2.asp

I would definately suggest reading Tom's Hardware guide to power supplies before purchacing one.  
http://www4.tomshardware.com/howto/20021021/index.html
They also have some informative PS comparison material here:
http://www4.tomshardware.com/howto/20030609/index.html
http://www4.tomshardware.com/howto/20040122/index.html

Leew, you should be careful with that estimate, computers now are using MUCH more than that.  The specifications for the Nvidia 6800 was something like 150W on its own!  With the setup that is described here I don't think that you'll have a problem with a 350 W supply as long as your other compoents (video card, HDs, CD drives...etc) aren't absurd power hogs.  As the first tom's hardware guide shows, often the rating of the power supply is not the amout it can in actuality handle.  

UPS's are very good as well to have, their batteries usually last about 10 years before a new one is needed.  
0
Enterprise Mobility and BYOD For Dummies

Like “For Dummies” books, you can read this in whatever order you choose and learn about mobility and BYOD; and how to put a competitive mobile infrastructure in place. Developed for SMBs and large enterprises alike, you will find helpful use cases, planning, and implementation.

 
LVL 96

Expert Comment

by:Lee W, MVP
ID: 12518320
There's nothing wrong with my estimate.  I did not say it was fact and I encouraged the purchase of a device to calculate that.  MOST people do not have $400 video cards, especially people who describe their systems as above.  The faster thiings get, the more power they tend to take, but even the NVidia card is not going to draw 150 Watts of power while being generally idle.  When playing Unreal Tournament at 100 fps, sure, but not when idle.
0
 
LVL 3

Expert Comment

by:RyanCh
ID: 12518401
However one cannot look at their purchacing options based on the idle power draw from their PC.  While it is true that very few people have $400 video cards, the purpose was to show an extreme example.  I have seen several problems when people under-estimate their power consumption (I thought that the device linked was excellent), but it is usually best to err on the safe side.  You are correct on the estimates on the idle load, It is just better to be safe and do your calculations of power under load.  It is like overclocking, one measures the max temperature under load, not while idle.  

0
 
LVL 96

Expert Comment

by:Lee W, MVP
ID: 12518420
Fair enough - but keep in mind what the question was asking.  
0

Featured Post

How Do You Stack Up Against Your Peers?

With today’s modern enterprise so dependent on digital infrastructures, the impact of major incidents has increased dramatically. Grab the report now to gain insight into how your organization ranks against your peers and learn best-in-class strategies to resolve incidents.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
GPO Not Applying 5 74
Copying out Cisco backups from SolarWinds 13 120
Migrate Thunderbird to Outlook 6 91
Weather Channel Nag Sreen Problem 6 40
If your app took Google’s lash recently, here are the 5 most likely reasons.
Healthcare organizations in the United States must adhere to the guidance of both the HIPAA (Health Insurance Portability and Accountability Act) and HITECH (Health Information Technology for Economic and Clinical Health Act) for securing and protec…
An overview on how to enroll an hourly employee into the employee database and how to give them access into the clock in terminal.
Finding and deleting duplicate (picture) files can be a time consuming task. My wife and I, our three kids and their families all share one dilemma: Managing our pictures. Between desktops, laptops, phones, tablets, and cameras; over the last decade…

739 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question