[ntp:questions] 10 identical PCs, but different clock drifts.
David J Taylor
david-taylor at blueyonder.neither-this-bit.nor-this.co.uk
Mon Mar 2 17:33:57 UTC 2009
ryad.bek at gmail.com wrote:
> Hi everybody,
> I've bought 10 PCs with identical hardware (motherboard,...).
> The PCs are located in the same room and running identical
> configurations for 4 days now.
> They are synchronized using garmin 18 GPSes.
> I've just checked the NTP's loopstats file and it seems that all drift
> are different.
> Here are the reported drifts (4th column of loopstats file) :
> As all hardware are the same and brand new, I was wondering if you
> find that normal or if there is a problem with my HW config?
It's most likely that all the timing elements (quartz crystals) are not
exactly on the same frequency. The allowed tolerance on a consumer-cost
crystal could be as bad as 0.01%, which is 100 parts per million (ppm).
You are reporting values up to 24 ppm. NTP allows up to 500 ppm.
More information about the questions