4

The system clock of my PC (not a laptop) runs behind. What could be the cause?

2
  • As alex said in the top answer, "consider marking the answer as accepted if you thought it was helpful. It benefits all of us :)"
    – Josh Hunt
    Sep 11 '09 at 8:48
  • Not really an answer but make use of ntp servers, there's a setting in Windows called "Sync time with internet servers". Use that and you time will always be accurate.
    – vava
    Sep 11 '09 at 12:49
15

Your CMOS battery that maintains the BIOS (and clock) information could have run out. Change it, it is usually a CR2032 battery and really easy to swap out on your motherboard.

alt text

1
  • This indeed did the trick. I looked at my motherboard's manual, where I found the type of the battery needed. And indeed, it was a common battery type (CR2032 like you said). Again, thanks for solving my problem.
    – Dimitri C.
    Sep 12 '09 at 21:26
4

Another potential cause not listed here is the RTC crystal is failing or not behaving.

alt text

3
  • This comment requires much greater clarification.
    – John
    Mar 1 '19 at 22:35
  • 1
    10 years later... I used to design motherboards and have seen (very few) instances where the RTC crystal didn't work. I didn't characterize the failure, I just replaced the part.
    – hanleyp
    Mar 31 '19 at 15:49
  • Okay, yes, just wait until the Internet has been around for 50 years! I read a bit about RTC crystals though it would be desirable to edit the post in a way that technical consumers could understand along with what action(s) they should take.
    – John
    Mar 31 '19 at 18:40
3

CMOS battery, bug in the OS, I have seen it under systems with a heavy load losing time. Possible when you run down the battery and it goes to sleep or hibernation you lose time. If it's a new laptop I wouldn't worry about the CMOS battery, just use NTP.

1
  • Specifically use ntp.org (or one of the country/regional sub-domains). Most OSs will query on a regular interval to keep things correct.
    – Richard
    Sep 11 '09 at 8:55
2

possibly a weak cmos backup battery?

2
  • Is that on the motherboard? Do you think this can be replaced?
    – Dimitri C.
    Sep 11 '09 at 6:59
  • yes and easily - someone seems to have answered with a picture of it as well :)
    – Journeyman Geek
    Sep 11 '09 at 7:50
2

Check your reginal settings (double click on the clock in the taskbar). You may need to check if the daylight savings box is correct and that your laptop believes it is in the correct timzone.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.