[ntp:questions] Re: Ntpd accuracy

David J Taylor david-taylor at blueyonder.co.not-this-bit.nor-this-part.uk.invalid
Wed Jun 8 08:34:17 UTC 2005

Eric Liu wrote:
> Hi all,
> I am testing Nptd on office LAN. The server is my office PC(a dell
> computer, P4 2.8G, 256M RAM, Windows 2000 sp4).

> We can see that the offset varys in a very large range. How can I
> make the offset much more regualr?  After our hard work, can I have
> 1ms accuracy?  If there are many clients(in fact, there will), 1ms
> accuracy means among all clients, relative to each other.

Eric, using your office PC as a reference server isn't a good idea.  One 
of the PCs on my networks runs Windows 2000 SP4 and is used an "Office 
PC".  The offsets I see are plotted here:


Certain programs completely clobber any accurate timekeeping, including 
Sun's JVM.  For comparison, look at a Windows box with no interactive use:


Within a millisecond or two is the best I can get.  People report better 
accuracies with UNIX servers and GPS reference clocks.  I am using 
Internet references via a cable modem connection.  All my PCs are shown 


What reference servers does you Dell PC have?


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