Detecting CPU throttling on over temperature

Daniel O'Connor doconnor at
Thu Sep 10 02:41:07 UTC 2009

On Wed, 9 Sep 2009, Robert Noland wrote:
> > I am pretty sure it would be throttling but I think that works by
> > maintaining the frequency but stalling the CPU some percentage of
> > the time. I have p4tcc loaded (in GENERIC) but it doesn't show up,
> > I only get..
> Is this a core2duo?  IIRC, they generally don't go into TCC until
> around 100C.  I did pull the c2d cpu docs at one point trying to look
> at cpufreq.  If you are bored, you can grab the docs from intel and
> double check.

Hmm, I only managed to get it to 75C or so..

Unfortunately the remote system which was exhibiting the problem has 
been fixed and the onsite guy doesn't have time to pull it out and 
break it again :(

The coretemp source suggests that there are 2 max junction temperatures 
for Core2Duos - 85C & 100C.

However I just realised the "faulty" system has an E2140 in it which has 
a 65W TDP, whereas the bench system has an E7500 with a TDP of 35W - I 
guess that could explain the difference.

Daniel O'Connor software and network engineer
for Genesis Software -
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
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