[ntp:questions] Timekeeping broken on Windows XP with multimedia timer enabled (-M option)

Alan greigaln at netscape.net
Wed Jan 20 18:44:09 UTC 2010

Would like to get to the bottom of this as well. Using 4.4.6-o with -M , 
I get "Frequency error 3030 PPM exceeds tolerance 500 PPM". Considering 
that without =M the frequency modification is only about 5 PPM then 
obvioulsy something very strange is going on. It seems that even if the 
timer precision is increased by another program then time immediately 
starts to drift rapidly by hundreds of milliseconds.

David J Taylor wrote:
> Alan,
> I hope you get this fixed.  Here's what you can get with XP with the MM 
> timer enabled:
> Windows XP LAN-synched to a stratum-1 server, 32s poll for local 
> servers, 1024s poll for Internet backup servers:
>  http://www.satsignal.eu/mrtg/narvik_ntp-b.html
> Windows XP acting as a stratum-1 server:
>  http://www.satsignal.eu/mrtg/feenix_ntp_2.html
> Both PCs running  "ntpd 4.2.6-o Dec 09 11:48:30.27 (UTC-00:00) 2009 (1)" 
> from Dave Hart's site.  Both PCs have Intel, not AMD processors.  Note 
> the reduced offset on the monthly graphs in week 1 and week 2 - it was 
> so cold here we kept the heating on 24 hours a day.  PC Narvik has been 
> rebooted about three times since the middle of week 2, hence the three 
> positive transients.
> On PC Narvik, Services Manager, Path to executable is:
>  C:\Program Files\NTP\bin\ntpd.exe -M -g -c "C:\Program 
> Files\NTP\etc\ntp.conf"
> Now you happen to mention processors, I realise that the PC where the 
> timekeeping is poor with the more recent versions of NTP (i.e. 4.2.5 and 
> later) both have AMD processors.  Maybe a coincidence?
> Cheers,
> David

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