is power management bad for your monitor?

Palindroman · Post by **Palindroman** » Tue Apr 17, 2007 12:55 am

One important thing that makes the systems I sell low power systems, is the fact that I preset the Power Options in the Control Panel. I let the system go into standby (Suspend to RAM) after 20 minutes, and the monitor after 5 minutes. Now somebody told me lately that this is real bad for the monitor. It goes into standby very fast and so people will wriggle their mouse and turn it back on straightaway. When done too many times the fragile LCD monitor will break down.

Is this true? Is it better to let the monitor go into standby after 10 or 15 minutes (or more)? From an energy saving point of view it's best to let the monitor go into standby mode as soon as possible, but replacing a broken monitor is not an option from any standpoint, of course.

Elixer · Post by **Elixer** » Tue Apr 17, 2007 3:00 am

This is not true for LCD monitors. LCD monitors are basically 'instant on' and therefore there is no state change for anything in the monitor and therefore almost no wear and tear from turning on and off. This is however true for old CRT monitors. It's bad for CRTs to be turned on and off all day.

jaganath · Post by **jaganath** » Tue Apr 17, 2007 5:13 am

LCD monitors are basically 'instant on' and therefore there is no state change for anything in the monitor

surely the backlight undergoes a state change?

sareiodata · Post by **sareiodata** » Tue Apr 17, 2007 5:23 am

jaganath wrote: surely the backlight undergoes a state change?

that may be so...but you must consider the fact that a LCD monitor comes with a 3 year warranty...they must have thought of this issue...and if after 3 years the LCD does fail...oh well...by that time a similar monitor might cost 3-4 times less then it used to (that is if you could find a similar one)... From the last year if I remember correctly a standard 19''LCD dropped in price something like 30% or more.

jhhoffma · Post by **jhhoffma** » Tue Apr 17, 2007 5:36 am

I remember in high school (mid-90s), when we had our first computer class using old IBM 386/486 PC clones, running Windows 3.11 for Workgroups, Wordperfect 5.1, and Lotus 1-2-3 for spreadsheets. Those were top-o-the-line systems back then.

The were worried that the power buttons in the monitors would wear out, so they told us to power down the system and then shut off the surge-protector instead of using the power buttons. Not really on topic, but it's what I thought of.

Palindroman wrote:It goes into standby very fast and so people will wriggle their mouse and turn it back on straightaway. When done too many times the fragile LCD monitor will break down.

How is that any different than still having the monitor turned on when the system shuts down? It's a non-issue, and I wouldn't worry about it.

Bigg · Post by **Bigg** » Wed May 23, 2007 12:42 pm

I usually put 10 mins sleep on systems I set up for people (on the somewhat rare occasion that I become the family "geek"). I find that five minutes drives people NUTS, and 10 minutes saves almost as much power, with no NUTS factor.

jessekopelman · Post by **jessekopelman** » Wed May 23, 2007 2:17 pm

I agree with Bigg that 10 minutes seems to be the sweet spot. 5 minutes and you get too many accidental power saves (which don't actually save anything, since the user just moves the mouse and goes back to using the monitor).

SlaveToSilence · Post by **SlaveToSilence** » Sat Aug 18, 2007 9:30 pm

i've gone for days without realising that i had left my monitor on 1 minute screen saver, because i use it none stop. and i mean wake up, use computer, go to sleep and repeat.. then i'll be reading something especially interesting with my hand off the mouse and it will go to screen saver

i think i might be a little bit addicted

Capsaicin · Post by **Capsaicin** » Mon Aug 20, 2007 5:10 am

I always have the "blank screen" screensaver kick in a few (5-10) minutes before my monitor goes into power save. This prevents most accidental power cycles for me.

Oops, looks like a necro post.

SlaveToSilence · Post by **SlaveToSilence** » Mon Aug 20, 2007 9:45 am

when i get my power meter im going to see if it uses any extra power to turn back on, and also compair the blank screen screensaver (i use that one too) to standby and also see if a blank whte background uses any more than a blank black one

subsonik · Post by **subsonik** » Mon Aug 20, 2007 10:58 am

jaganath wrote:
LCD monitors are basically 'instant on' and therefore there is no state change for anything in the monitor
surely the backlight undergoes a state change?

When you turn down the brightness on an LCD monitor, the backlight changes state 250 times per second. It is dimmed by means of turning it on and off very quickly. Turning it on and off every few minutes won't hurt then

Actually, TFT backlights have a limited lifetime of about 20K hours until brightness dropped to 50% of the original value. Turning off the monitor when not used is much better for its longevity.

Good ol' CRT monitors is another story, they don't like turning on and off a lot.

Reachable · Post by **Reachable** » Mon Aug 20, 2007 2:16 pm

It's bad for CRTs to be turned on and off all day.

Good ol' CRT monitors is another story, they don't like turning on and off a lot.

I wouldn't be so sure of that. I remember reading a few years ago (when CRTs were still the predominant type) that all the monitor manufacturers recommended that monitors be turned off when not in use, and that repeated off and ons didn't damage them one bit.

I can't offer any documentation for this, but I think it's possible that this is one of those issues that lies in the myth-prone realm. As for the LCDs, the best person to ask is probably Mr. Samsung (assuming you can get an answer, that is.)

subsonik · Post by **subsonik** » Mon Aug 20, 2007 11:09 pm

Of course, you should turn them off when not in use. But you shouldn't give them powercycles every few minutes.

In contrary to TFT's, CRT's do contain components which are stressed on each powercycle. Especially the heating filament in the tube.

KayDat · Post by **KayDat** » Mon Sep 10, 2007 10:00 am

I dunno if this is relevent, but I also turn down the brighness on my LCD monitors. While old CRT's might benefit the old "black background on white text" trick in saving power, it wouldn't work on LCD's because LCD's create black from turning a pixel "on", blocking the backlight. So I figured that turning the backlight down would save power.
Luckily, my main monitor has color profiles, so normal usage, I'd have the brightness on 0, and if I game or watch any videos, I'd change it back to normal. That way, I reduce eye-strain as well =)
What do you guys think?

nutball · Post by **nutball** » Mon Sep 10, 2007 10:25 am

SlaveToSilence wrote:when i get my power meter im going to see if it uses any extra power to turn back on, and also compair the blank screen screensaver (i use that one too) to standby and also see if a blank whte background uses any more than a blank black one

I can tell you what my Dell 24" TFT does as measured with my power meter.

Normal operation: 55W
PC-make-the-screen-go-black-but-don't-actually-turn-off-the-backlight screensaver: 52W
Shut the PC down but leave the monitor to go into it's power save mode: 0W

Well 0W clearly isn't 0W because the LED on the monitor power button is on, but it's presumably <~1W. Which is good I think.

HueyCobra · Post by **HueyCobra** » Sun Sep 16, 2007 7:55 am

Dan's Data looks at power consumption with a Dell 3007WFP-HC:

Daniel Rutter wrote:At this minimum brightness, my new power meter reckoned my monitor was consuming only seventy-something watts, depending on what was displayed on the screen. An all-black screen was somewhere between 67 and 70 watts; an all-white one was about 77.

Winding the brightness up to maximum boosted the all-black power consumption to 133 watts, with an all-white screen now consuming 142.

Even if these numbers aren't very accurate, it's still clear that the power to be saved by using darker screen colours, or the silly "Blackle" black-Google site, is completely dwarfed by the power you can save by running your monitor at a lower, and probably ergonomically superior, brightness. It doesn't hurt to save the single-digit watts that darker screen colours can achieve, but the difference between the most I could make the monitor draw at minimum brightness and the least it drew at maximum brightness is more than fifty watts.

SoopahMan · Post by **SoopahMan** » Sun Sep 16, 2007 7:37 pm

Elixer wrote:This is not true for LCD monitors. LCD monitors are basically 'instant on' and therefore there is no state change for anything in the monitor and therefore almost no wear and tear from turning on and off.

Whoever sold you this was selling you "Whatever's new is perfect," and just like last decade's new stuff, it isn't.

LCDs operate with a backlight. It's a fluorescent light. Power cycles on a fluorescent light are:

1) What kills them.

2) The most inefficient thing you can do to them.

5 minutes is too aggressive, and you will absolutely end of life that bulb faster if you encourage a habit of turning it off while the user is using it, causing them to instantly turn it back on.

The result is an entire monitor with plastics and poisonous materials being put in the ground that will MORE than eliminate any small gains of saving a little electricity.

The ideal solution comes in 2 parts:

1) Be reasonable with power saving. 15 minutes for the monitor to turn off.

2) If you can, try to run a screensaver for a very short time before the power save kicks in. 10 seconds is ideal but Windows will probably only let you get down to one minute. This warns the user they're about to lose their image, and they'll shake the mouse then, without the backlight having to powercycle.

My favorite solution to this is on Ubuntu/Gnome, a version of Linux. After 15 minutes the screen slowly fades to black. If you let it keep going it goes all the way to black then the monitor turns off. Smooth transition and an obvious signal to the user that if they want to keep looking at what they're doing, shake now.

specular · Post by **specular** » Mon Sep 17, 2007 6:56 am

If both what subsonik and SoopahMan is true, then those of us who use our screens at lower brightness levels are killing their lifespan. Could that be true?

lm · Post by lm » Mon Sep 17, 2007 11:42 am

SoopahMan wrote: The result is an entire monitor with plastics and poisonous materials being put in the ground that will MORE than eliminate any small gains of saving a little electricity.

Please tell me, is it a myth, or do old pc's really end up in landfill in the US?

Around here, any home electronics or utilities can be left for free to places that sell similar stuff, and they have to send them to problem waste center, which takes care of extracting any poisons safely and recycling as much as possible.

I recently bought something from the US and they made sure to tell me that they sent me the lead free version of their product because I am in EU. So they have a product in both lead and lead free, price is the same, and they happily keep selling the leaded version to people in US.

truckman · Post by **truckman** » Mon Sep 17, 2007 10:54 pm

SoopahMan wrote:LCDs operate with a backlight. It's a fluorescent light. Power cycles on a fluorescent light are:

1) What kills them.

2) The most inefficient thing you can do to them.

5 minutes is too aggressive, and you will absolutely end of life that bulb faster if you encourage a habit of turning it off while the user is using it, causing them to instantly turn it back on.

The result is an entire monitor with plastics and poisonous materials being put in the ground that will MORE than eliminate any small gains of saving a little electricity.

The ideal solution comes in 2 parts:

1) Be reasonable with power saving. 15 minutes for the monitor to turn off.

2) If you can, try to run a screensaver for a very short time before the power save kicks in. 10 seconds is ideal but Windows will probably only let you get down to one minute. This warns the user they're about to lose their image, and they'll shake the mouse then, without the backlight having to powercycle.

I agree with your suggestions, though the effect of turning the backlight on and off isn't quite as dire as you suggest. While they still wear out more rapidly during cold starts than during normal operation, LCD backlights use CCFLs, which are less affected by power cycling than CFLs and the large tubular florescent lamps that use a heater to start. This Wikipedia page about compact florescent lamps discusses CCFLs in the "Other CFL Technologies" section. CCFL backlights have rated lifetimes of 20000 to 50000 hours, which is about 2-6 years if you leave them on 24x7.

It is possible to replace a worn out LCD monitor backlight and not just dispose of the entire monitor.

White LEDs are also starting to displace CCFLs as LCD backlights, which makes power cycling the backlight even less of an issue.

jessekopelman · Post by **jessekopelman** » Tue Sep 18, 2007 11:53 pm

specular wrote:If both what subsonik and SoopahMan is true, then those of us who use our screens at lower brightness levels are killing their lifespan. Could that be true?

No, you are misunderstanding. What is (relatively) bad is having the backlight go from completely off to an on state. This is the most stressful act. Various changes to degree of on-ness are no big deal. Running at a reduced brightness might even be good for the lifespan of the backlight/LCD (it won't get as hot).