System clock losing time even when powered on

Discussion in 'Tech Support' started by crazybob, 4 Dec 2007.

  1. crazybob

    crazybob Voice of Reason

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    In the last few days, I've noticed that my computer clock is losing time. I am checking it against my cell phone, which is synchronized daily from what I assume is a reliable source, and if I force the computer to check with a time server it will temporarily match my phone. However, it's losing as much as a minute every 12 hours.

    I'm accustomed to computers losing time if they have a weak CMOS battery and are left off frequently, but I have never run into a computer losing time when it's left on 24 hours per day. Is this some strange and evil curse, or am I wrong to assume that the battery only runs the clock when the computer is off?
     
  2. JoeJones

    JoeJones What's a Dremel?

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    It's quite possible that you are losing time due to a high constant load on the processor which doesn't have 'time' to track the time proplery. I've never seen it before but it's certainly a possibility.

    Presumably the CMOS battery is constantly running the real time clock, just when you've powered up the system the operating system takes the time from it to start with and then calculates it on it's own afterwards without re-syncing.
     
  3. capnPedro

    capnPedro Hacker. Maker. Engineer.

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    Try changing the CMOS battery anyway? They only cost like £1...
     
  4. lworbey

    lworbey What's a Dremel?

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    As far as I'm aware, the CMOS battery runs the system time full stop. Just because the PC is switched on doesn't meant the battery is no longer used, changing the battery should cure your problem :idea:
     
  5. crazybob

    crazybob Voice of Reason

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    Thanks for the quick replies. I guess I'll be changing my battery, then. If I make the change quickly enough, will I be able to swap batteries without losing my BIOS settings?
     
  6. RinSewand

    RinSewand What's a Dremel?

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    If it's loosing a minute every twelve hours, can you not just set it to sync itself with a time server every day? I did this with my laptop, and as long as you aren't bothered about the odd minute it works fine.

    On a side note, one of the time servers i get a choice of doesn't sync proper and is out by at least ten minutes, so you might not want to use the default one.

    RwD
     
  7. lworbey

    lworbey What's a Dremel?

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    I'm not sure about losing settings when you change the battery, I would think you shouldn't lose any BIOS settings, just the date/time, the battery only keeps the clock going AFAIK, the BIOS settings should be stored but I could be wrong :eyebrow:
     
  8. JoeJones

    JoeJones What's a Dremel?

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    The BIOS settings are stored in CMOS memory which requires a constant power source either from a battery or mains supply. Taking out the battery AND unplugging the PC will eventually lose the settings in the CMOS. There's usually enough residual charge for the extremely low power requirements of the CMOS left in the board after the battery is taken out to keep the settings for a good 10-30mins.
     
  9. SteveyG

    SteveyG Electromodder

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    I seem to remember having this problem with my pc a long time ago, it ended up being a conflict between the motherboard and Windows' power management settings which was causing me to lose as much as an hour in a day.
     
  10. cpemma

    cpemma Ecky thump

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    As a common way of re-setting the BIOS is to remove the battery "for a minute or so" I should write down your settings before changing the battery. ;)
     
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