I'm a long time sufferer of this, found a way to live with it ensuring
that my laptop simply under performs, ... until recently.

Previously I requested verification of normal operating temperatures
-- how hot is 90-100 C for P-M1.73Ghz really??  At full power mine is
like this, apparently this is really killing it, but I don't think so.
 Any one know for sure _before_ commenting?

I'm concerned that there hasn't been any absolute statement about how
this should work and what to expect.  Seems that it works ok for
enough people not to worry about it.  But why does Windows use this
CPU so much better??

However, I can now get much better than before results from a fresh
Feisty Kubuntu install using the following:

echo "115:0:95:80:0" > /proc/acpi/thermal_zone/THR0/trip_points

and polling seems to be at 1.

From my point of view, I don't care about the 115 because the chip
will thermally sort itself out -- besides it never reaches this, and
this is the point, I don't want a shutdown!  Every now and again I see
a temp of 102, 105, 107.. these are all just blips that immediately
return to 90 something and only happen at full pelt which isn't that
often for typical operation.  The fan does its job, the chip scales
itself to 1300 (something) as and when.  So I'm happy to let it rip
right to limit (hence the 95)

The other numbers don't really matter, its for the board which doesn't do a lot.

I'm running in ondemand, and can run performance (though don't see the point).

I've noticed now that my machine has started using C-States properly
also.  I had 3+ hours instead of the usual <2.  Some of this I'm sure
was due to the previous install of X being a bitch after several days
of use.  Uptime is now 18 days and its running as nice as it does from
first boot.

I watch the acpiinfo all the time (recommended during this problem)

  watch acpitool -e

Can people please start posting this also for comparisons:

  CPU type               : Intel(R) Pentium(R) M processor 1.73GHz
  Min/Max frequency      : 798/1729 MHz
  Current frequency      : 798 MHz
  Frequency governor     : ondemand
  Freq. scaling driver   : centrino
  Cache size             : 2048 KB
  Bogomips               : 1598.15
  Processor ID           : 0
  Bus mastering control  : yes
  Power management       : yes
  Throttling control     : no
  Limit interface        : no
  Active C-state         : C2
  C-states (incl. C0)    : 5
  Usage of state C1      : 10 (0.0 %)
  Usage of state C2      : 19506306 (38.2 %)
  Usage of state C3      : 10372833 (20.3 %)
  Usage of state C4      : 21221897 (41.5 %)

  Thermal zone 1 : ok, 54 C
  Trip points :
  -------------
  critical (S5):           115 C
  passive:                 95 C: tc1=2 tc2=5 tsp=300 devices=0xdf83ce50

  Thermal zone 2 : ok, 48 C
  Trip points :
  -------------
  critical (S5):           82 C

Q's:
where does the default trip information come from?
Is the default trip information wrong?
what should they be?
exactly what is the relationship between these trips, the cpu and the
CRIT-shutdown?
does the kernel have any control of the fans for this chip?
how is it possible that this doesn't affect every P-M1.73Ghz owner?

btw, you should at least be using a 686 kernel, shouldn't you?  If
running at 798Mhz is your only issue with the proper kernel, this is
quite normal!!  Your nice CPU is saving trees when you don't do
anything useful on the computer.

Rob.