When you have a CRT monitor, it takes more energy to create white pixels than it does to create black pixels. The brighter the pixels are, the more power they're using. Everyone knows that, right? That's why they have screen savers that turn your screen black, so its using less power.
What I didn't know is that LCD monitors work just the opposite. LCD monitors are effectively always displaying white pixels, but they can selectively block out those pixels. However that means it takes MORE energy to block out white pixels in order to create black pixels. So a screen full of black pixels is actually your worst case scenario for power consumption.
The moral of that information? Skip the screen saver just have your LCD turn off after a few minutes.
ID:181933
 May 29 2009, 6:14 am
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Honestly, it wasn't necessary to say all that for one to know that turning off the monitor is the better option.
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Foomer wrote:
The moral of that information? Skip the screen saver just have your LCD turn off after a few minutes. Like Vermolius just said, you'd expect everyone and his uncle to do that anyway, LCD or not. So I'll include a different moral of that info: LCDs' black color is a much crappier and brighter one than CRTs', since LCDs don't just "turn off the lights", so to speak, when they're displaying black, like CRTs do. But then again, people should generally know LCDs' color reproduction tends to be crappier overall than CRTs'. (Damn you the guy who invented them!) | |
Of course LCD's still use tremendously less power than a CRT no matter what color you are displaying.
Also, I know that some LCD HDTV's are turning the backlight off on the display to display "blacker" blacks. It's just a matter of time before that is common place in most LCD displays. But yes, turning your monitor off is always the better option. Most monitor's also automatically turn themselves off after a certain period of time of inactivity. | |
I've always had my LCD do that. It's speed of coming back on is just so quick it's not worth the cost of power to have to not wait.
Also, ScreenSavers were not for reducing power use. The use is in the name "screen saver". They were created to prevent burn in from having a single image sitting on the monitor for too long. Even a black screen can cause burn in(even burn in, mind you, but burn in none the less), so a ScreenSaver has a moving object or changing screen so that it can't be burned in. | |
Kaioken wrote:
Foomer wrote: Good point, but a lot of companies that I've worked for tend to leave their monitors running 24/7 with only a screen saver. I was mostly interested in pointing out that, with LCDs, having the black screen saver running in most of the time is actually worse on energy usage than not having it. | |
I looked a little bit into this, and it seems though it's using "more energy", it's really just about a one watt difference between full white and full black. So even if you had five hundred monitors running overnight with full black screen savers, you're only talking about an extra 6 kilowatts, which equates to about 6 pounds of CO2 on average, per night, or just about one ton of CO2 per year.
Obviously it's best to save energy where possible, but some people (and this is not directed at you!) seem to enjoy nitpicking the hell out of some things. Still, it's definitely interesting that black does use more energy, however small the difference. | |
So in effect a white desktop displayed for 100 hours would be less energy drainy than a black one? Or would the different not be of consequence.