M.I.5¾ wrote:
> "Mark" <markalroberts******.com> wrote in message
> news:1165992463.103242.3700@80g2000cwy.googlegroup s.com...
> > Hi
> >
> > I recently received my new Dell 640m with Core 2 Duo processor -
> > lovely! Except I got an annoying high pitch noise - barely detectable,
> > but annoying people with good hearing!
> >
> > So, looking on the forums, it seems people are reporting the same
> > problem on various machines, and it seems to be related to the CPU and
> > the frequency it runs at setting up some sort of resonance.
> >
> > The advice was to download RM CPU Clock utility (freeware, and very
> > good!) and disable the "Enable Popup Mode" tickbox in the "Advanced CPU
> > Settings" section.
> >
> > http://forum.tabletpcreview.com/showthread.php?t=3516
> >
> > I have tried this, and it really works! I can clearly detect the noise
> > stopping/starting as I toggle this setting.
> >
> > I cannot immediately detect and down sides to this change of setting -
> > the RM Clock readme states:
> >
> > "Enable Popup mode (auto C3/C4 to C2) - when this option is off, any
> > bus master traffic causes the chipset to return from C3 or C4 state
> > into C0 (working) state. When this option is on and the chipset
> > observes a bus master request, it will take the system from C3 or C4
> > state into C2 state and enable bus masters. This will let snoops and
> > memory access occur. This setting is available only for ICH6-M and
> > ICH7-M."
> >
> > I would really appreciate if anyone translate this into real-world
> > performance/heat/battery life information for me :)
> >
>
> The CPU (and indeed other chips) draw their power in pulses rather than
> continuously. As you note, this can sometimes create beat frequencies with
> the power supply circuits (which also operate in pulses). The toggle you
> made has altered the pulse pattern sufficiently to make the beat frequencies
> inaudible. The heat output and battery life are unlikely to be detectably
> affected. As for performance, it might be noticeable, if you compared itto
> another popup mode enabled machine. Otherwise, you probably won't.

Thanks for the response; does this mean you'd not be bothered about the
increase of Core temp from 40 to 44 degrees? Guess I could run some
battery life tests.

Hmm, makes me wonder if i can change this pulse frequency some other
way without effecting performance...