Motherboard RTC issue - PC won't keep proper time - Page 1
Forum section: electronics / repair

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: July 22, 2014, 02:57:59 pm
content: So I have this out-of-warranty Asus p5e series motherboard (desktop board) and the darned thing won't keep proper time in its BIOS or the operating system. The drift is about +4-5 minutes per 3-4 week period. I've replaced the coin-cell battery (it measured fine); although I didn't think it to be the issues, I've tried with a fresh install of Windows and the same thing occurs. All peripheral components (ie ram, etc) test good. Time syncing is set to time-a.nist.gov and I have an exception in the pfsence router to allow traffic to/from the timeserver.My curiosity has gotten the better of me here... Any direction?

author: robimarko
author_rank: Regular Contributor
timestamp: July 22, 2014, 02:59:46 pm
content: RTC clock is drifting

author: Monkeh
author_rank: Super Contributor
timestamp: July 22, 2014, 03:12:21 pm
content: RTC isn't used booted.Adjust the W32Time service to actually be remotely useful:http://serverfault.com/questions/111954/how-to-set-a-frequent-period-for-ntp-client-to-sync-with-the-ntp-serverEven once you convince it to sync on a useful interval, it still won't keep good time.

author: XOIIO
author_rank: Super Contributor
timestamp: July 22, 2014, 03:16:25 pm
content: Quote from: robimarko on July 22, 2014, 02:59:46 pmhttp://www.dailystormer.com/wp-content/uploads/2014/04/2178890-youdontsay.jpglol

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: July 22, 2014, 03:45:17 pm
content: Quote from: robimarko on July 22, 2014, 02:59:46 pmI love this...Quote from: Monkeh on July 22, 2014, 03:12:21 pmI'll make the registry change but I agree this will still be an issue. I'd love to figure out what is going on.

author: Monkeh
author_rank: Super Contributor
timestamp: July 22, 2014, 03:47:35 pm
content: Once booted, the clock is maintained by software: this sucks, this drifts, you can't avoid it. W32Time is crap and will only be able to help you to keep it within a few seconds.Does the clock measurably drift while shutdown?

author: David Hess
author_rank: Super Contributor
timestamp: July 22, 2014, 04:05:41 pm
content: The usual solution is to just use NTP, SNTP, or external hardware like a GPS while the system is operating to keep the time adjusted. If you are desperate, you could replace the 32.768 kHz clock crystal or maybe trim the oscillator frequency.

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: July 22, 2014, 04:36:36 pm
content: Quote from: Monkeh on July 22, 2014, 03:47:35 pmPC is a HTPC so it stays on always. I've adjusted the recording time for the tv so it catches the entire program but this is a poor solution.Quote from: David Hess on July 22, 2014, 04:05:41 pmI'm going to check the operating frequency of the clock crystal to see if this is the issue. Thanks.

author: Monkeh
author_rank: Super Contributor
timestamp: July 22, 2014, 04:38:45 pm
content: Don't bother twiddling with the RTC, it's not the problem.Set NTP up.

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: July 22, 2014, 04:45:53 pm
content: Quote from: Monkeh on July 22, 2014, 04:38:45 pmOK, thanks again; will-do.

author: rob77
author_rank: Super Contributor
timestamp: July 22, 2014, 04:53:21 pm
content: exactly NTP time synchronisation and storing the current time to the RTC chip on shutdown. i don't know how to do this on windows, but most linux distributions have a hwclock binary which can be called from shutdown scripts (and many distributions are doing this by default) to store the current time (synced from NTP) to the RTC. so when you shutdown the machine - the RTC gets updated and it won't drift too much till the next start-up (when the NTP kicks in again).

author: David Hess
author_rank: Super Contributor
timestamp: July 22, 2014, 05:20:59 pm
content: Quote from: StubbornGreek on July 22, 2014, 04:36:36 pmThis is not an uncommon issue. I have a couple of Windows systems which have the same problem to a lessor or greater degree.The NTP client that I run, Tardis2000, in place of the built in NTP client also calculates and applies a correction factor to correct for the clock running fast or slow so if NTP connectivity is lost, the time drift is still kept low. On my old server without it, the OS time drift would be -29.361 seconds per day. On my workstation, it would be +46.441 seconds per day.Quote from: David Hess on July 22, 2014, 04:05:41 pmThe RTC clock crystal only matters for the BIOS and when the OS reads the current time from the RTC. Somewhere there is a crystal used for the CPU clocks which could be adjusted but again, that is a pretty desperate measure although I have heard of it being done in connection with precision timekeeping.

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: July 22, 2014, 09:53:43 pm
content: Thanks, David. Appreciated...

author: David Hess
author_rank: Super Contributor
timestamp: July 22, 2014, 10:01:25 pm
content: Quote from: rob77 on July 22, 2014, 04:53:21 pmI do not know how Windows (or Tardis which I use) handles this either. Since the real time clocks on my systems seem accurate, I assume they are being updated.