Thinkpad Thermals

[Kevin Oberman]

> From: Jesse Guardiani <jesse at wingnet.net>
> Date: Fri, 04 Mar 2005 05:09:46 -0500
> Sender: owner-freebsd-mobile at freebsd.org
> 
> Kevin Oberman wrote:
> 
> >> From: Jesse Guardiani <jesse at wingnet.net>
> >> Date: Fri, 04 Mar 2005 13:01:21 -0500
> >> Sender: owner-freebsd-mobile at freebsd.org
> >> 
> >> Howdy!
> >> 
> >> My IBM Thinkpad A30p's ATI video chip got cooked last year,
> >> leaving me with an unreadable screen full of artifacts. I
> >> finally bought a replacement mobo a few days ago and installed
> >> it this evening. It's now running artifact free! Yay!
> >> 
> >> Anyway, I'm no longer running FreeBSD on this laptop. I'm
> >> currently running Gentoo Linux. But it would be trivial
> >> to switch back if needed.
> >> 
> >> I'm using gkrellm under linux to monitor my CPU temp, and
> >> I'm noticing that it runs quite hot. The fan doesn't kick
> >> in until the CPU hits 80C! That's a little too close for
> >> comfort, IMO.
> >> 
> >> I think I remember seeing other posts from Thinkpad users
> >> mentioning high temps under ACPI. Has anyone found a way
> >> to cool these things down?
> > 
> > Jesse,
> > 
> > Is it running at or near 80C when idle, when in typical use, or when
> > building something BIG (CPU running at >95% for minutes).
> 
> More or less idle. It fluctuates between 70C and 80C. Just playing an
> MP3 I'm at 77C right now. Is this normal acceptable temp for a thinkpad?
> Or should I be targeting the 40C range like I do with my desktop machines?
> 
Acceptable? I suspect it is, although it seems a bit warm to me, too. My
T30 idles at about 48C and playing MP3s pushes it up about 5 degrees, so
your's is running a bit hotter than mine.

Laptop CPUs almost always run hotter than desktop systems. Just think
about the fans and the big heat sink on the CPU. Your laptop has no space
for things like that. P4s are especially bad and P4-Ms are just a bit
better. The newer P-Ms (often call Centrino) do MUCH better, but their
internals are very different from the P4..probably more like a
P3. Getting heat out of a laptop is a real problem.
> 
> > I believe that the A30p is a P4-M CPU. It will turn itself off (hard,
> > like a power cut-off) before the CPU dies, but that is NOT a good
> > thing. That does not happen until the CPU reaches a frightening 135C.
> 
> Actually, I think mine is a P3-M at 1.2ghz. It uses PC133 SODIMMs, and
> /proc/cpuinfo reveals this:
> 
> Intel(R) Pentium(R) III Mobile CPU      1200MHz
> 
> I think it's the A31p that uses a P4-M.

Sorry. The P3s generally run much cooler than the P4s. Is your fan
running? It should be at those temperatures. It's under BIOS control in
my T30, but you would have to dump your ACPI tables to see if there is
any fan control available.

> > If you are running 5-Stable or 6-Current you should load cpufreq and
> > acpi_perf. These will give you a large number of CPU "frequencies"
> > visible in dev.cpu.0 and settable in dev.cpu.0.freq. This provides
> > fine-grained control.
> 
> I asked this question here mostly because I know a lot of people on this
> list run Thinkpads, and I remember more than one complaining about cooling
> issues.
> 
> Again, I no longer run FreeBSD on this laptop. I run Gentoo. Linux has
> various different daemons capable of throttling the CPU though, and I
> currently have an "on-battery" runlevel setup that runs the speedfreq
> daemon with a preference for "powersave". I could install something in
> my default "on-AC" runlevel that regulates CPU based on load even when
> on AC...
> 
> But... is 80C normal under load? Running a frequency daemon won't change
> the under-load temp unless I cap the horsepower or introduce some sort
> of temp related frequency feedback control as you describe below.
> 
> Hmmm... well that's interesting: Just to test it out, I unplugged the
> AC and ran it for a while, still playing the same MP3. It leveled out
> at 66C in the "powersave" profile, which means that the CPU is running
> at just 799.457mhz instead of 1199.185mhz (performance).
> 
> Is 66C acceptable temp for a laptop? It's definitely a better temp, but
> It would really stink if my 1.2ghz had to be run at just 800mhz all the
> time to avoid cooking things.

Once again, I can't define "acceptable". It is not so hot as to be
frightening, but it does sound like it's running warmer than I would
expect. Dust? Blocked air intake/outlet? Those can real impact
thermals. And, of course, fan problems can be a big issue.
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634