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I have an Acer laptop (AS4820TG, it's about 2 years old), and I recently installed Windows 8 to a partition I made on my SSD (now I'm dual booting 7 and 8). My laptop's always had pretty good battery life.

On Windows 7, fully charged, windows sometimes estimates that I'll get 8.5 hours. Of course, that never happens, but nonetheless I can still squeeze a good 5-6 out of it if I'm saving power in as many ways as possible.

However, with Windows 8, on a full charge, I only get a prediction of perhaps 1.5-2 hours. It usually lasts not much more than one, even if I keep it in power saving mode and don't do anything intensive.

The one thing I know is hurting me is that with the fresh install, I lost the ability to automatically power off the optical drive. Other than that, I can't figure out what's slashing my hours! Even if it's unsolvable, can someone suggest what else might be the culprit? Thanks!

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screen brightness perhaps. – Glenn Ferrie Nov 1 '12 at 6:32
No offense but screen brightness is pretty obvious and I definitely had that in consideration. It's something else... – Matt Nov 1 '12 at 7:52
Check with your manufacturer for any BIOS updates - I realised my laptop wasn't automatically dropping its CPU speed when under low load but was instead running at full speed all the time. A BIOS update cured it – Graham Wager Nov 1 '12 at 9:14
My BIOS is all the way updated too :/ I am looking at a 2h01m estimate with 97% battery remaining right now. Aside from the optical drive thing I mentioned, it also seems that my cooling fan is more active than it is on Windows 7. I'm not sure how much of an effect these two things can have, but I really don't think it could shave off 6+ hours... Any other ideas? I really would love to make a permanent switch to Win8 sometime soon, but if battery life's this bad, it just can't happen. – Matt Nov 1 '12 at 18:45
No one can suggest anything? – Matt Nov 3 '12 at 3:23

probably a really late reply but if you have an Nvidia graphics card download the actual Nvidia driver so optimus can disable the card when it's not needed, the fan is most likely the graphics card one. Exact same problem as you and that worked for me

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Didn't they do away with Optimus and hybrid graphics in Windows 8? – Bigbio2002 Dec 28 '12 at 17:10

Sorry for the late answer, it happens to me and I think I found out the reason.

  1. Open your Intel Graphics and Media Control Panel, and right click for properties.
  2. Open the Power tab
  3. Change all the power settings to Maximum Battery Life.
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I had similar situation when I installed windows 8 too. I used to get 4 hours of backup on 7, but only 2-2.5 on 8.

Things I've done:

  1. Ran Windows Update.
  2. Installed all latest device drivers.
  3. Set my brightness to minimum, and battery mode to Power Saver.

Installing latest device drivers is very important because, in my case, it turned out my wifi and bluetooth drivers weren't written, and optimized for 7.

Now, I have solid 3.5 hours of backup on 8.

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Thanks for the response! I'm definitely all updated though. I've gotten as many drivers working as possible, including things like wifi and I don't have bluetooth at all. That's why it's baffling me that battery life is so darn short. – Matt Nov 1 '12 at 7:54

these may help you:

  1. Set up a lower brightness for your screen
  2. Reduce CPU maximum work percentage in energy settings (you do this by creating or editing a profile)
  3. disable your wireless when not needed and any other plugged usb devices
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protected by Community May 26 '13 at 16:36

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