[ntp:questions] refclock on Windows graphs

David J Taylor david-taylor at blueyonder.neither-this-bit.nor-this.co.uk
Tue Mar 17 23:07:24 UTC 2009

Unruh wrote:
> Maybe when someone finally put refclock support into chrony you will
> have
> your wish.

Not until it runs under Windows.

> It sounds like your temp changes causing rate changes on a
> scale
> that ntp cannot properly cope with. (ntp is terrible at coping with
> changes-- a purposeful design decision by Mills). I get about 3-5
> usec as
> average offset, but the freq changes are only about .1PPM , not 3PPM.
> The
> room is not particularly air conditioned, but the temp variations
> over the
> day are probably less than 5C not 20C.

Here it's probably a variation of at least 10C.  The computer CPU use 
itself is fairly constant throughout the day, so it may well track ambient 


Another PC in the same room running a FreeBSD system has about half the 
jitter, but far less offset - PC Pixie at the top:


I recall trying some of the motherboard temperature monitoring software, 
but probably not for that PC.  I'll look again.


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