# Question about laptop's screen frequency



## JMAA (Sep 17, 2009)

I just wanted to waste less battery, but my laptop is always a battery hog, maybe because the screen or something else. So I want to ask: is there a nice screen frequency I can use, in Ghz/Hz/Whatever?
Or is there another reason this computer monster wastes so much battery?
The only thing I know is that the screen is always bright (when it was running out of battery, it became so fucking dark but nicely usable and sightable).
And the laptop is already set to laptop energy settings in Windows.


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## ToeClaws (Sep 17, 2009)

Technically speaking, refresh rate on a laptop is a little different than it was traditionally on a CRT.  CRT's drew their images by a Cathode ray gun firing an image at a luminous phosphor screen.  The rate at which the gun swept from end to end was the refresh rate.  

LCD's are completely digital, where each liquid crystal is controlled by it's own dedicated circuit.  The refresh rate on an LCD only serves to broadcast the colour command to those circuits.  Typically, most LCDs will accept an input of 60 to 75Hz, though it has no real effect on the end display.  

That said, it also has no effect on the power consumption.  Saving power on a laptop can be done a number of other ways:


reduce the brightness of the screen
set the hard drive spin-down time to something lower (and also have enough RAM that it doesn't need to use the drive constantly for paging)
Disable/shutdown unused wireless and wired Ethernet interfaces
Remove extra function cards if they are not needed (PCMCIA, Express cards)
Remove unused Thumb Drives
Remove unused CD/DVD discs
Make sure your OS has the drivers and/or options enabled to take full advantage of the laptop's power-saving features


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## Runefox (Sep 17, 2009)

Yeah, the screen being on maximum brightness probably has something to do with it. You might want to pop open your laptop's power management driver (they usually come with one), and set the LCD brightness on battery to maybe half or less. The only time you really need the screen on max is when it's on AC power. Also, refresh rate has nothing to do with it.

Also, ToeClaws has the /thread on this one.


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## Yaps (Sep 18, 2009)

The more brightness you have, the more power it uses up. Try to change it back into the darkest when your in a fairly dark room. Once you get use to it, you won't tell the difference. 

I personally switch on the brightness when I am using it in a bright sunlit area... Otherwise, Toeclaws summurised most of it already. 

I believe that LCD brightness is the biggest factor on battery life...


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