AJR

One of the first returns by Google directs you to a TechNet explanation
site.

<mfreeman@columbus.rr.com> wrote in message
news:1176582434.018916.276000@q75g2000hsh.googlegroups.com...
>I am running a new Dell Inspiron E1705 (Intel Core 2 Duo 2 GHz, 2G
> RAM) that came with Vista Premium. Every few minutes, there is a
> "hiccup" when playing MP3 files.
>
> I ran the "Reliability and Performance Monitor" and found that when
> the hiccups occur, there is a big spike in "C1 Transitions/sec." (from
> zero to over 6,000) and a simultaneous dip in "C3 Transitions/sec."
> from an average around 2,000 to zero. There are occasional C1 spikes
> without a C3 dip and those don't seem to affect Media Player. This
> would seem to indicate an issue related to CPU power states.
>
> I am running on AC/Power in "High performance" power mode. It is set
> with a minimum processor state of 100% and to never sleep or
> hibernate. I also noticed a corresponding spike in the "dwm" process
> CPU usage, so I disabled the Sidebar. "dwm" doesn't spike any more,
> but the C1/C3 issues remains the same. I am running the machine
> disconnected from any network when this occurs, and there are no other
> apps active (other than Windows Explorer).
>
> Does anyone else have this problem? Can anyone point me to a good
> explanation of what C1 and C3 transitions are, how they interrelate,
> and what OS settings can impact them?
>
> Thanks,
>
> Mark
>