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 Post subject: LCD power?
PostPosted: Sun May 17, 2009 4:21 pm 
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Location: Seattle
I am wondering about the power consumption of various LCD monitors. I have a Sceptre X20B Naga II that uses 50 watts.
Some of the 24 inch monitors on Newegg state anywhere from 30 to over 100.
BenQ G2400WD 50 watts max

SAMSUNG 245T 130 watts max.

SAMSUNG 2443BWT 50 watts typical

Acer H243Hbmid 30.5

I think some might be playing fast and lose with how things are measured.
The 26 inch monitors on Newegg take considerably more power, but the 25.5 inch take no more than the 24s. Not sure what to make of that. Is Energy Star important, or is that like "deluxe" or "Heavy Duty", words which have lost meaning.
My 2Wire router/modem takes 5 watts.
My Sonic Impact amp that is hooked up to the computer takes 5 watts.

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PostPosted: Sun May 17, 2009 8:30 pm 
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Not sure exactly what the question is, but I'll try to answer a few.

The reason why the 245T takes so much more power than the other monitors is because it uses a different panel technology (S-PVA as opposed to S-TN). S-PVA gives better color reproduction and viewing angles than TN, but TN generally has faster response times and is cheaper. That would account for the descrepency in power consumption between similar-sized monitors.

As for the Energy Star certification, it is still important, but not very noteworthy as every monitor should be energy star certified. This means that although it isn't as big a deal as it once was, it's not the case that the requirements for certification have gotten any less stringent; rather, it is just that it has become standard to become compliant. In the end, it is very good for keeping things like idle power consumption low.


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 Post subject:
PostPosted: Mon May 18, 2009 5:27 pm 
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Yes, that is what I wanted to know. Thanks, tehfire. I just threw in those bits about the router and amp wattage as I was having fun playing with the Kill a Watt.

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 Post subject:
PostPosted: Mon May 18, 2009 7:32 pm 
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Energy Star rated only means it has an energy saver mode (screen turns off) and consumes less than a few watts when in this mode. There isn't a spec for power usage when on.

Panel type is one big difference in consumption, the other biggie is the backlight and it's inverter circuitry.

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 Post subject:
PostPosted: Tue May 19, 2009 6:21 am 
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I have a HP LP3065 30" 2560x1600 S-IPS display.

My power meter shows these readings (including the PC (idle) and UPS):

Hard off: 106W (+/- 1W) (on/off switch behind unit)
Soft off: 111W (+/- 1W) (on/off switch in front of panel)
Min bright, black screen: 160W (+/- 2W)
Min bright, white screen: 176W (+/- 2W)
Max bright, black screen: 235W (+/- 2W)
Max bright, white screen: 250W (+/- 1W)

So we see, that the monitor alone consumes (including UPS inefficiency):

soft off: 5W
Min bright black screen: 54W
Min bright white screen: 70W
Max bright black screen: 129W
Max bright white screen: 144W

And we see that min brightness uses just 40%-50% of power compared to max brightness, depending on if the screen is black or white. That's a massive difference.

Also we see a very weird phenomenom, black screen on a regular lcd monitor uses less power than a white screen??? I truly did not expect this. I thought this was the case on CRT displays, but not with LCDs?

Myself, I use this at min brightness, because that's what my eyes prefer.

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 Post subject:
PostPosted: Wed May 20, 2009 10:21 am 
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CA_Steve wrote:
Energy Star rated only means it has an energy saver mode (screen turns off) and consumes less than a few watts when in this mode. There isn't a spec for power usage when on.


I spoke too soon. There is a specification for power usage when on...but you can drive a truck through it. Good news is the specs are being tightened (version 5) and go into effect October 30, 2009. The spec can be downloaded here.

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 Post subject: Dell G2410 9W
PostPosted: Wed May 20, 2009 12:40 pm 
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Location: UK
This might be interesting. My Dell G2410 uses 9W at 30% brightness (My preferred level) and I am very happy with the image quality for Word/Surfing/Games.

I am also pleased with my new Laptop http://www.silentpcreview.com/forums/vi ... hp?t=42833 whose screen uses about 3W.


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 Post subject:
PostPosted: Fri Oct 30, 2009 6:48 pm 
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I did some power consumption measurement on two different 20" LCD see this Link

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 Post subject:
PostPosted: Mon Nov 02, 2009 6:36 am 
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Might be of interest Clicky


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 Post subject:
PostPosted: Mon Nov 02, 2009 8:51 pm 
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Gohan wrote:
Might be of interest Clicky


Thanks for the Link really useful to see power consumption at min and max brightness. The 30" are taking much more power at min that I will have expected.

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