By: Jonathan Kwan
February 24, 2007

Nowadays, there's a huge emphasis on efficiency, and power consumption versus performance -- simply due to the high cost of electricity and environmental concerns. However, in your house, what uses lots of electricity and what doesn't? Should you leave your computer on all day? Let's count in some determining factors by checking power consumption of a few common technology items today.

We will be conducting our tests using Seasonic PowerAngel. This is our first edition of these reports, so if you are wondering how much electricity certain items use (That's reasonably testable), please contact us or post in our forums.

Specifications of the Intel based laptop in our tests above:

System: Dell Inspiron 6400 (15.4" @ 1440x900)
CPU: Intel Core 2 Duo T7400 2.16GHz (Merom, 4MB L2 Cache - SpeedStep enabled)
RAM: Super Talent T667SB1G/S PC2-5300 (2x1GB, 5-5-5-13)
Graphics: ATI Radeon X1400 256MB Hypermemory
Optical Drive: Toshiba-Samsung 8X DVD Burner
Hard Drive: Hitachi 160GB SATA

Specifications of the AMD based computer:

CPU: AMD Athlon 64 3000+ (Newcastle, 512K L2 Cache - Cool & Quiet enabled)
CPU Cooling: Arctic Cooling Freezer64 Pro
Motherboard: Asus K8V-X Motherboard
RAM: Corsair 2x512MB, Single Channel, DDR400 @ 2.5-3-3-8
Hard Drive: Western Digital 80GB 7200RPM 8MB Cache (NTFS)
Graphics: ATI All-In-Wonder Radeon 9800 Pro
Arctic Cooling VGA Silencer Rev. 3 @ 2400 RPM
Sound: Creative Sound Blaster Audigy 2
Floppy/Flash Reader: Mitsumi 7-in-1 Flash & Floppy Reader
Optical Drive: Pioneer DVR-108 Multiformat DVD Burner
Optical Drive: Liteon 16x DVD Drive
Case: Thermaltake Matrix VX
Power: OCZ Modstream 450W PSU

Specifications of the Intel based computer:

CPU: Intel Core 2 Duo E6300 @ 2.80GHz (400MHz*7)
CPU Cooling: Scythe Infinity
Motherboard: Asus P5W64-WS Professional
RAM: OCZ Special Ops Edition Urban Elite PC6400 2x1GB @ 4-4-3-9, 1:1 with CPU
Case: Thermaltake Aguila (1x120mm LED, 1x120mm)
Power: Seasonic M12 500W
Graphics: BFG 7600GT
Sound: Creative X-Fi XtremeMusic
Optical Drive: NEC AD-7170A 18X DVD+/-RW
Hard Drive: Seagate 7200.10 320GB 16MB SATA2

These results were obtained prior to our Intel test system changes to an Asus Radeon X1950 Pro and four modules of OCZ's FlexXLC PC2-6400.

More information on the Thermaltake Muse NAS RAID. The results for the Thermaltake Muse NAS RAID are used without a hard disk for our power consumption tests.

The laptop is tested when the battery is full, so it is not charging. LCD brightness is turned to the max unless otherwise specified.

As you can see in our test results above, the laptop used significantly less power than both desktops -- and with the LCD turned off and idling, it used 10W less out of 29W idle with the LCD turned on. This becomes very apparent that the screen will use most of your battery when unplugged. There's a good reason why everyone says to dim the LCD to prolong battery life.

The most interesting aspect is that both of our desktops, although none very powerful by today's standards, both uses very little power in relative. At 180W, our Intel Core 2 Duo E6300 overclocked with our Seasonic M12 500W power supply is quite efficient. (Same tests with a Tagan TurboJet 1100W used up to 205W of power.)

Does this mean you should go out and buy a 300W power supply? The answer is definitely no -- simply because it is not about the raw power consumption, but the amount of power supplied on each rail. One could load down on the +12V rail but not the +5V rail, while another user might have it reversed -- therefore power supply manufacturers usually do their best to balance out and estimate how a typical user will build their computer in order to distribute power.

How much do displays use? Take a look at a 17" CRT monitor that I've tested at a friend's house. Power usage of 87W on a 16" viewable screen is not very efficient compared to 54W power consumption on my 20" Dell 2005FPW widescreen LCD display at maximum brightness.

On the other hand, my 32" Panasonic LCD HDTV uses 118W of power at full brightness.

Well, I got a set of "value oriented" Logitech X-530 speakers I bought a few years back. The purpose is not for music (I am rarely at home anyway), I just use them for hearing Windows sounds only haha. Anyway, I was kind of curious if different kinds of music, such as one with more instruments and lots of bass, versus more vocal music, will have different power consumption. The results are not surprising.

Random songs pulled out of my large collection:

Linkin Park - Numb, Crawling
Evanescence - My Immortal
Kelly Clarkson - Because of You, Since U Been Gone
Green Day - Wake Me Up When September Ends, Give Me Novacaine
The Killers - Somebody Told Me
Red Hot Chili Peppers - Dani California
POD - Strength of My Life
The Fray - Over My Head (Cable Car), How to Save a Life

Yes, I actually purchase my albums for the sound quality encoded to my Creative Zen Vision:M!

In our results above, I listed the maximum power consumption recorded while playing the songs at the same volume. Was it surprising that Linkin Park songs used more power? Not really, in my opinion.

A few other miscellaneous items I decided to test today. A color laser printer warming up or during printing progress sure used a lot of power. On the other hand, I wasn't too surprised that my Aerus central vacuum system's powerhead with lights used 110W of power.

What I was surprised in is that my Motorola cable box uses 13W of power. I mean, it's a cable box...

Anyway, regarding the night light, is a very simple unit that I bought cheap from Home Depot, utilizing an incandescent based bulb. Using 4W of power, I don't think it matters whether you get those high efficiency panel emission lights or these -- the power usage is very low anyway, and I must also mention that these are actually brighter and actually makes a difference.

In general, most things do not use a lot of electricity. What we know is that appliances that do a lot of mechanical work, used for heating, or cooling, will use much more electricity than a TV or a computer. If you have a huge power bill, it probably is not your computer -- it's probably your stove or fridge (Or someone is vacuuming the house too much!).

If you really want to cut down on your power bill all the way down to the detail, consider using a laptop or a high efficiency power supply for your desktop. Turn off that cable box at night, and speaking of nighttime -- don't waste your money on those 'high efficiency' light emitting panels. Traditional night lights are brighter, nicer, cheaper, and power usage difference is minimal.