[ntp:questions] Re: Windows timekeeping - sudden degradation - why?

Danny Mayer mayer at ntp.isc.org
Sun Dec 11 01:53:40 UTC 2005

John Allen wrote:
> This thread has intrigued me because I think I may have a similar problem.
> My Windows XP system ran Terje's NTP 4.2.0a happily from May 2004
> until sometime in the last month - I can't be as precise as David Taylor.
> My PC was synchronizing to my server running Linux also with NTP 4.2.0.
> Using NTPMonitor occasionally, I was seeing offsets typically 20-50 ms
> from reliable low-stratum servers - more than satisfactory for me and I
> paid very little attention to it. The SP2 upgrade went smoothly some
> months ago.
> Sometime in the last few weeks NTP on the PC has completely lost the
> ability to synchronize with the server. I'm seeing offsets increasing by
> several seconds an hour - they are consistent across my server and
> distant stratum 1-3 servers. The offsets are alway negative which means
> (I think) that the PC's time is running faster than the server.
> I've tried all the obvious things - installing later and earlier
> versions of ntpd, removing applications running in the background...none
> of these seems to affect the behaviour of NTP in the slightest. I've
> made some fairly major changes to the PC in the last 2 months, some of
> which I'm not keen to reverse - like installing Visual Studio C++
> Express Edition, .NET 2.0 runtime, Windows SDK, BIOS upgrade, so there
> are plenty of things which could have clobbered NTP.

The only thing on this list that is likely to have an affect is the BIOS
upgrade. Nothing else would affect the runtime. The only other thing
that is likely to affect the clock is Windows update since we have
absolutely no idea what it may change.


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