On May 14, 12:42 pm, John McGaw <nob...@nowh.ere> wrote:
> mar...@hotmail.com wrote:
> > What is the expected accuracy for the time clock on a PC
> > with Intel Core-2 6300 at 1.86GHz, 32-bit Vista?
>
> > My Vista synchronizes with an Internet server on Sat at 9pm.
> > I checked on Sat after 9pm and the PC time clock was accurate
> > to every second. On Sunday evening it was 2 seconds fast,
> > today on Monday it is 4 seconds fast, i.e. it seems to gain
> > 2 seconds per day.
>
> > Does it mean that the latest PC technology still cannot ensure
> > time clock accuracy at least -/+ 1 second per week?
> > Are there any expansion boards available to rectify the problem?
>
> What it means is that your PC uses the cheapest possible crystal for its
> time standard and that has almost nothing to do with "the latest PC
> technology". It has almost everything to do with saving a penny. As for
> expansion boards, why bother? If you have a reliable internet connection
> you can synchronize your clock more frequently and achieve +/- 1 second
> accuracy very easily. I synchronize my machines once per day using a
> free program called atomic.exe but there are others out there which are
> equally free and which serve the same purpose. You can even, with a bit
> of registry diddling cause Windoze to update more frequently than their
> pre-ordained weekly interval although for some reason MS seems to have a
> difficult time with this relatively simple task.
>
> There are numerous sites and pages covering the whole subject of time
> synchronization and a search will turn them up readily. You can even, if
> you feel daring enough set up your own time server synchronized directly
> to the national standard and then synchronize other computers on a
> network directly to that.
>
> --
> John McGaw
> [Knoxville, TN, USA]http://johnmcgaw.com


The problem with frequent synchronizations is that it may lead to
timestamps
that are out of order. For example, if you have a server program
running in the
background 24/7 around the clock that collects real-time events and
saves a
timestamp of each event you may end up with events that are out of
order
when a sync sets the clock back a few seconds. Syncing once per week
Sat/Sun night is fine but not more frequent than that.

Besides, Internet synchronization is rather primitive because the
protocol
is very primitive. You always have to check visually the time after
so called
synching. I would rather do it only once per week.