[ntp:questions] questions] WinNT Port Performance Counter Stability and Drift

Steve Kostecke kostecke at ntp.org
Mon Nov 11 00:26:41 UTC 2013

On 2013-11-09, David J Taylor <david-taylor at blueyonder.co.uk> wrote:

>Charles Elliott wrote:
>> The result of reading the timestamp counter can vary wildly due to
>> EIST (speed step technology), turbo modes, and owner overclocking, in
>> addition to differences in CPUs, as noted. There is quite a bit about
>> this on the Internet. As I recall, most writers recommend not using
>> it, but if one must, using it only for short interval timing and
>> after repeatedly measuring the frequency of the counter. The latter
>> can take quite a bit of time, as it should be done several times, and
>> for different interval lengths, and taking the average or median of
>> the results.


> Charles, and mail list admins - just to let you know that your message did 
> not appear to reach the newsgroup:
>   comp.protocols.time.ntp
> at least on my feed from Eternal-September.

An article from Charles made it to the Google Groups mirror of c.p.t.n:


Looks like a problem with your free news server.

Steve Kostecke <kostecke at ntp.org>
NTP Public Services Project - http://support.ntp.org/

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