John Allen wrote:
> John Allen wrote:
>
>> Richard B. Gilbert wrote:
>> >My guess would be that your local clock has a frequency error well in
>> >excess of 500 parts per million! If that is the case, you will
>> >probably have to replace the mother board to fix it.
>
>
>> As you say, the hopeless inaccuracy of the system clock might be cured
>> only by a new motherboard, although it seems strange that for more
>> than a year it seemed to work fairly well.
>
>
> I really was going to give up on this when I made what could be a useful
> discovery. While reading of recurrent problems with system clocks on
> nForce2 motherboards, eg these threads:
> http://www.nforcershq.com/forum/1-vt19631.html
> http://kerneltrap.org/node/4872
>
> I found references to possibly using a different HAL (Hardware
> Abstraction Layer). I then did what was probably not wise, which was to
> change from
> "ACPI Uniprocessor PC" to "Advanced Configuration and Power Interface
> (ACPI) PC". I also set the BIOS option "FSB Spread Spectrum" to "disabled".
>
> By good fortune this did not stop the PC working but it has had the
> result that the system clock has been very stable for 24 hours and NTP
> is now working properly, with offsets of no more than 7 ms (from the NTP
> server on my LAN) over long periods:
>
>>ntpq -c "rv 0"
> assID=0 status=4644 leap_add_sec, sync_ntp, 4 events, event_peer/strat_chg,
> version="ntpd 2004 May 07 8:37:39 (1)"?, processor="unknown",
> system="WINDOWS/NT", leap=01, stratum=4, precision=-20,
> rootdelay=58.614, rootdispersion=153.312, peer=7996, refid=192.168.0.5,
> reftime=c74ae7bc.223db21c Wed, Dec 14 2005 19:49:32.133, poll=9,
> clock=0xc74ae8e7.5bfd448c, state=4, offset=-7.045, frequency=-7.005,
> noise=3.010, jitter=0.955, stability=1.529
>
> It may be that this HAL change only works because it disables the APIC
> (Advanced Programmable Interrupt Controller); at any rate, it has made
> me realise how far one can go from what initially appeared to be an NTP
> issue.
>
> I've noticed that some other threads in this newsgroup have concerned
> PCs with nForce2 motherboards, so this could be a useful hint. However,
> changing HALs should not be done without careful reflection and a
> willingness to reinstall Windows if something goes wrong.
>
> This site (in German) gives some more information:
> http://www.planet3dnow.de/artikel/diverses/nf2config/3.shtml#config_apic
>
> as does this:
> http://support.microsoft.com/?kbid=821893
>
> Moral of the story: if NTP seems to stop working properly and you have
> an nForce2 motherboard (a) the problem is quite possibly not NTP and (b)
> you may not need a new motherboard...
>
Can you add this to the our Support Twiki? It's always useful to have
this kind of thing easily available and not to have to stumble across it.
Danny
> John
>
> --
>
> John Allen
> Bofferdange, Luxembourg
> allen{at}vo{dot}lu
> http://www.homepages.lu/allen
>
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